CA2187010C

CA2187010C - Method and appartus for remote control of wellbore end devices

Info

Publication number: CA2187010C
Application number: CA002187010A
Authority: CA
Inventors: Paulo S. Tubel; David Eugene Rothers; Albert A. Ii Mullins; Mark Mccorry
Original assignee: Baker Hughes Inc
Current assignee: Baker Hughes Holdings LLC
Priority date: 1995-02-10
Filing date: 1996-02-07
Publication date: 2008-07-15
Anticipated expiration: 2016-02-07
Also published as: GB0006148D0; AU716324B2; GB9619568D0; NO964290D0; GB2344911A; GB2302607A; AU4776296A; US6021095A; WO1996024752A2; GB2302607B; WO1996024752A3; GB2344910A; GB0006151D0; GB2344911B; NO964290L; CA2187010A1; GB2344910B

Abstract

A wellbore remote control system is disclosed which includes (1) a transmission apparatus for generating at least one acoustic transmission having a particular transmission frequency, (2) a reception apparatus which includes an electronic circuit (preferably digital) which detects and identifies the acoustic transmissions, and which provides an actuation signal to an electrically-actuated wellbore tool if a match is detected.

Description

2 PGT/L1S96/0a612 ~ METHOD AND APPARATUS FOR REMOTE CONTROL OF WELLBORE
ENDDEVICES 2187910 .

1. Field of the Invention:
The present invention relates in general to date transmission systems, and in particuiar to data bwmmission systems which may be utilized in welibor+es to communicate remote control signals through fluid columns disposed therein.
2. Description of the Prior Art:' In the oil and gas industry, it has been one longstanding objective to develop data transmission systems which do not require the utilization of electrical conductors to carry control signals between welibore locations which are separated by great distances. Experience has revealed that data transmisaion systems which require the ub'lization of electrical conductors extending between communicatlon nodes in a wellbore are advantageous when data must be communicated within the wellbore at extremely fast transmission rates, or when large blocks of data need to be transferred between communication nodes; however, the utilizatjon of electrical conductors has severai serious disadvantages inciuding: (1) since most wellbores include regions which are exposed to corrosive fluids and high temperatures, a long service life cannot be expected from a data transmission system which utiGzes elecbical conductors; (2) since most wellbores extend for substantial distancsss, data transmission systems which utilize electrical conductors are not generally considered to be cost effective, particulariy when such systems are utilizsd only infrequently, or in a limited manner (3) since all wellbores define fairiy tight operating clearances, utifization of a wireline conductor to transmit data may reduce or diminish the operai;ing ciearance through which other wellbore operations are performed; and (4) since wellbores typically utilize a plurality of threaded tubular members to make up tubular sb-ings, utilization of an electrical conductor to transmit data within the wellbore complicates the make-up and break-up of the tubular string during conventional operations.
SUBSTITUTE SHEET (RULE 26) WO 96/24752 2187,010 PCTlI1S96/0I6I2 Accordingiy, the oii and gss industry has moved away from the*

utilizMon of eiectrical, conductor data transmissicn systems (frequently referred to as "hardwire" syatrantis), and toward the utilization of preasure changes in a fluid column to transmit data within the wellbore. One exaneple of the extensive use of fluid columns within a wellbore to transmit =
date is that of ineasur+ement~nrhile-drilling data transmission s,ystems, also referred to as "MWD" systems. Typically, these systems are utilized only in drilling operations. Generally, a plurality of sensors are provided in a tubular subassembiy located within the battam hole assembly, near the rock bit which is utilized to disintegrate the formation. The electrical sensors detect particalar wellbore parameters, such as tatnperature, pressure, and vibration, and develop electrical signais corresponding thereto. The eiectrical signals are converted into a digital signal stream (generaily multiplexed sensor data) and utilized to develop a plurality of pressure changes in a fluid column, typically the tubing fluid column, which are sensed at the earth's surface and converted into a format which allows the drilling engineers to make decisions which alfect the drpling operations.
Some attempts have been made to apply the concepts of MWD data transmission systems to completion operations, during which the drilled wellbore is placed in condition for continuous productlon of oil and gas from selected wellbore regions.

One of the more interesting of the prior art approaches is that described and depictsd in U.S. Patent No. 3,227,228 to Bannisler. The Bannister reference is directed to a meUiod and system for remotely actuating coring devices which are located In a drilistring. The coring devices may be individually and selectivei,r actuated from a surface location, and function to auEomatically obtain core samples from the wellbore formation sunrouncling particular portions of the drill collar. The invention of the Bannister reference is sucoinctly summarized at Cckimn 1, commencing at line 58, as foliows:

"These and may other objects and advantages of my invention ar+e accomplished in one embodiment by having one or the drill collars SUBS77TUTE SHEET (RULE 26) wo 96124752 PCTI[iS96/01612 (hereinafter called a croring' collar) in the drill strin8 of a rotmy rig contain a plurality of sampie-taking devices and means for firing the devices in response to a remotely located wave energy source. The wave energy can be a controlled vibration of the drill string, a radio wave transrnis~on, or a pressure variation transmMed down the driN mud. ... When a fonnallion sample is to be taken the operation of one or more coring devics3s is seiectively controlled by wave energy transmission from a remote location."

The Bannister reference teaches the alLernative utilization of timee techniques for rernotely controlling the firing of the coring devices in a coring collar. Those techniques Include (1) applying vibration energy to the drillstring, (2) utilizing a pressure pulse generator to alter the pressure in the fluid column, or (3) utiliang a radio transmitter. All three of the albernetive actuation techniques are depicted graphicaily in Figure 1 of the Bannisterreference. The vibratory ener-gy supply 40 is depicted as being directly mechanically tinked to the drillstring. The radio transmit#er 42 is depicted as ulilizing an ant,enna to tiwsmit rad'w frequency actuation signals. The preasur+e pulse generator 41 is shown as commurlicating with the flowiines of the drilJing rig, to allow the direcE application of the pressure pulses to the fluid column in the weHbore. The Banniaterrefersnce uses the tarm "wave energy" to enconWass all three types of attsrnatjve achon systems. The broad objective of the Bamti.stev-invention is steted at Column

3, commencing at line 30, as fdlows:

"The coring collar 20 mounts a number of coring devices 21 that are fired by firing selector 22 (Fig.
2) controlled by wave energy tranamitted from a wave energy source at the surface to receiver 23 located in coring coliar 20. The coring devices 21 can be fired selectively at any desired forrnation level."

This is further elaborated on commencing at Column 3, line 74, as follows:

SUBSTITUTE SHEET (RULE 26) The coring devices 21 can be t~ed by several fiorms of contrdleq~,W~a.~re '~ origina~ing from wave energy sourde at the surface. The wave energy can be a vibration tranamitt,ed down the driQstring 8 from a vibration wave energy source 40 (Fig. 1), a pressure variatlon from a pressure wave energ)- souroe 41, or an eiectromagnetic tranarsission from a radio wave source 42. Each of these wave energy sources is oanveniently associabed with a rotary rig without int,erfering or significantly detaying the operation, as wi!l be described hereinafter.

fn the figures of the Bannister reference, the vibration transmitter is depict,ed in Figures 3, 4, and 5. The pressure pulse generators (two ait+ernative embodiments) are depicted in Figures 6 and 7. A radio frequency actuafion apparatus is depicted in Figure S. The remaining figures (Figures 9 through 14) depict the mechanical components af the coring tool itsetf.
The preasure puise transmission equipment Is described in the specif'icatton between Column 4, line 66 and Cdumn 5, line 68. Bannister plainly teaches the utilization of a"cfistFnct characterisfic" In the pressure signals, as stated at Column 4, commencing at line 66, which states as follows:

The coring devices can be fired by a pressure vibration having a distinctive characterintic transmit#ed down the drill mud 6. A pulse or a wave having a preset frequency can select which coring device is to be fired.

It is also clear from the Banvdstar r+eference that a high velocity pressure change is cantempiate& in all probability, the pressure change can be characterized as an acaustic pulse. The specification ciearly stat{es this commencing at Column 4, line 70, which states as follows:

One embodiment aFa pressure pulse firing system js iillusbrvrted in F7GS.1 and 6. The pressure pulse 40 source 41 fires an exploeive charge 75 when switch 76 is closed in a fluid filled explosion

4 SUBSTITUTE SHEET (RULE 26) chamber 77 connected through valve 73 to the stand pipe 7. brill mud circeiiatian is stopped, normally closed valve 78 I. open and normsiiy open valve 79 and 85 In the inlet and outlet pipe 17 and 15, respectively, are closed. The explosion creates a st,eep frant, high ampiitude pressure = variation that travels down the drill mud 6 inside driNstring 8 to the coring collar 20.
Thus, it appears that the pressure puise is probably traveling close to the velocity of sound for the particuiar transmission medium. The two different types of pressure pulse generators which are depicted in Figures 6 and 7 are described separately in Column 5 of the Bannister reference.
The embodiment of in Figure 6 is described as follows:

Disposed within coring collar 20 is a pressure responsive receiving means 80 (Fig. 6) that acbwkm a firing seiec6or 81 to selectevety fire the coring devices 21. The pressure variation flexes a diaphragm 94 cNspoeed In the wall of passage 30, transmitfJng a force through an inconmpressibie fluid 82 to a pist,on 83. An outward force (to the left as viewed In Fig. 6) Is applied to pisftn 83 by a spring 84 keeping contact 86 at the end of piston rod 87 frorn stationary contact 88. When the high ampiNxide pressure variation reaches the corirtg collar 20, the contacts 86 and 88 close an energizing circuit including battery 89 to a soienoid 96 that operates a pawl 90 and rotates a ratchet wheei 91 to a new position. At each position of ratchet wheel 91 an attached contact arm 92 connects with a fixed contact that doses an energizing circuit inciuding battery 93 to fire the electric detnnatAr in one of the coring devices 21. Each pressure pulse fires another one of coring devices 21 as the ratchet wheel 91 is progressively rnoved to new posifions.

The atternative embodiment of the pressure pulse generator of l=et}ure 7 Is described as foiEows, commencing at Column 5, line 25:

Another form of pressure resportsive receirring means that uses eiectronic techniques to duplicate the above describe eiectr+omechanicai

5 SUBSTITUTE SHEET (RULE 26) ayatem is illustrated in F6.'7. The present data miniaturizataon of electronic components facili#ates the compact arrangement of this apparatus, wherein the pressure variation is sensed by a pressuretesponsive transducer 100, preferably a piezoelectric device, and a vottsge propordonal to the pressure, after being ampQfied =
by amplifier 101, is coupled to a threshold limiter 102. The threshold limiter serves to prevent normal pressure variations in the drill mud B from firing the coring device 21 by producing an output signal only If the pressure-proportional input voltage exceeds a preset minimum. The Schrnidt trigger circuit Is one suitable type of threshold limiter, producing for each lnput pulse about (sic) a preset level an output pulse that is coupled to a univibrator 107, (a mono-stable multivibrator). to produce a pulse ihat is amplified in amplifier 103.
Each pulse activates a stepping switch 104 having an input to successively connect an input 105 to each of outputs 106, closing an energizing circuit inciuding battery 108 for the electr9c detonator of one of the coring devices 21.

Yet another alternative system, which Is not depicted in the drawings, is discussed for use in pressure pulse actuation, commencing at Cofumn 5, line 58 which reads as follows:

Another pressure wave firing system suitable for use in the present invention utjlizes a pressure source that generates an aiternating pressure variation in a single frequency in the drill mud 6.
The pressure wave responsive receiver includes a pressure variation transducer that produces an A.C. signal from the transmitted pressure wave, using a filt,er channel to fire one of the coring devices. As in the mechanical vibra#ion arrangement, other frequencies and filter channels can be incorporated to selectively fire additional coring devices 21.

The particular reference to the "mechanical vibration arrangement"
is an identification or the foregoing text which relates to the mechanical vibration actuated firing, which commences at Column 5, lines 48, which states as follows:

6 SUBSTITUTE SHEET (RULE 26) It is apparent that the vibration wave system previously described can be modified to operate on a series of pulses as In the pressure responsive system embodiment just described with reference to Fig. 7. In such an arrangerhent only one frequency need be used and the A.C.
generator 45 would be connected to vibrator 47 only for a moment to produce each vibratory pulse. The vibration response receiver Would include a band-pass filter preferably following amplifier 101 that responds only to the selected frequency.

SUMMARY OF THE INVENTION
It is one objective of an aspect of the present invbntion to provide a method and apparatus for communicating remote control signals in a welibore between a transmission node and a reception node, through a fluid column extending therebetween, wherein potential fluid leak paths are minimized in general, and in particular are minimized by sensing the acoustic transmissions having one or more identifying transmission frequencies through a rigid structural component of the reception apparatus at the reception node.

It is still another objective of an aspect of the present invention to provide a method and apparatus for communicating remote control signals in a wellbore between a transmission node and a reception node, through a fluid column extending therebetween, wherein the opportunity for error in the reception of the acoustic transmissions Is minimized by making the reception circuitry insensitive to acoustic signals having a frequency other than the one or more transmission frequencies uniquely associated with the particular reception equipment.

It is still another objective of an aspect of the present invention to provide a method and apparatus for communicating acoustic transmissions having one or more identifying frequencies in a wellbore between a transmission node and a reception node, through a fluid column extending therebetween, wherein the acoustic transmissions are generated In an automated manner by a fluidic circuit located at the

7 transmission node which is under the control of a data processing system.

It is still another objective of an aspect of the present invention to provide a method and apparatus for communicating acoustic transmissions In a wellbore between a transmission node and a reception node, through a fluid column extending therebetween, with a reception apparatus located within the wellbore at a desired location on a wellbore tubular conduit string, wherein detection of the acoustic transmissions uniquely Identified with the reception apparatus causes the actuation of a wellbore tool, and wherein said fluid column Is monitored for at least one fluid pressure change which provides a positive indication at a surface location of actuation of the wellbore tool.

When characterized broadly as a method, the present invention is directed to a method for communicating remote control signals in a wellbore between a transmission node and a reception node, through a fluid column extending therebetween. The method is comprised of a plurality of method steps. A transmission apparatus is provided at the transmission node, which is in communication with the fluid column, for altering pressure of the fluid column to generate an acoustic transmission having one or more Identifying frequencies which is composed of either positive or negatlve" rapid changes in pressure amplitude. A reception apparatus is also provided, but is disposed at the reception node. The reception apparatus includes: (1) a rigid structural component with an exterior surface which is in contact with the fluid column and an Interior surface which is not in contact with the fluid column, and (2) a sensor assembly which detects changes In elastic deformation of the rigid structural component, which is also maintained out of contact with the fluid column. The transmission apparatus is utilized to alter pressure of the fluid column in at least one predetermined pattern to generate at least one remote control signal having one or more acoustic transmission frequencies. Preferably, the generation of the acoustic

8 WO 96/U7S2 PCf/US96103612 transmissions is accomplished by a fluidic circuit which is under computer control. The reception apparatus is utilined to detect the frequency at the acoustic transmissions in the fluid column dwough changes in the elastic defonmation of the rigid structural cornponent In one embodiment, the sensor assembly includes a fluid body in conirnunication with the interior surface of the rigid structural component, but which Is not in communication with the fluid column. The fluid body is responsive to changes in the elastic deFamation of the rigid structural component Also, preferably, a pressure sensor is provided for directly sensing pressure changes in the fluid body to detect elastic deFormation of the rigid structural cornponent.t !n the alt,arnative embodiment, a strain gage bridge may be utilized to detect elastic deformation of the rigid structural component In the described embodiments of the present inventjan, the rigid structuret component comprises a mandrel member which at least partially defines the central bore to the wellbore tubular member. The mandrel member is a substantially imperforate component which contains very few, if any, potential fluid leak paths, thus allowing the present invention to be utilized in weilbore completions which are intended for extremely long service lives.
The present invention may be utllized to perform completion operations in a wellbore. A single transmission apparatus is provided at the wellhead for remote control signals which are transmittad to a piuraiity of reception apparatuses which are disposed at selected locations within a string of tubular members. A plurality cf weil8are tools are provided in the string in selective communicatton with the plurality of reception apparatuses. The wellbore tools may include (a) electrically-actuable wellbore packers; (b) eiectricaliy,acttiabie perforating guns; (c) electrically-actuable values; and (d) eiectricaliy-actuable liner hangers. The transmission apparatus may be utilized to generate particular control signals to selectively actuate the plurality of wellbore tools In a predetermined manner to complete the wellba+e. Typically, liner hangers may be utilized to hang casing off cemented casing segments. Cementing

9 SUBSTITUTF SHEET (RULE 26) operations should follow to cement all portions of the casing. Next, perforating operations should be conducted to perforate selected portions of the cased wellbore. Then, one or more packers should be set to isolate particular regions between a production tubing string and the cased wellbore. Finally, valves should be opened to allow the selective flow of wellbore fluids into the cased wellbore for production upward through the production tubing string. Three different electrically-actuated end devices are described and claimed which have special utility in completion operations.

Accordingly, in one aspect of the present invention there is provided a method of controlling a remotely located wellbore tool between modes of operation, comprising:
providing (a) an electrically-actuable wellbore tool, (b) an acoustic transmission sensor, and (c) a digital circuit for continually examining, during monitoring operations, detected acoustic transmissions and providing a control signal if a detected acoustic transmission defines a plurality of sequentially transmitted acoustic transmission segments, each defining a particular predetermined actuation frequency;
said digital circuit including:
(i) a detection circuit communicatively coupled to said acoustic transmission sensor for generating a pulse signal corresponding to each one of said acoustle transmissions;
(ii) a counter circuit communicatively coupled to said detection circuit for counting said pulse signal; and (iii) an enabling circuit for selectively enabling said counter circuit wherein said detection circuit, said counter circuit, and said enabling circuit cooperatively operate to cause the generation of said control signal;
securing said electrically-actuable wellbore tool, said acoustic transmission sensor, and said digital circuit to a tubular conduit string;
lowering said tubular conduit string within said wellbore to a selected wellbore location;
providing a wellbore fluid column in contact with a portion of said tubular conduit but out of contact with said acoustic transmission sensor;
generating an acoustic transmission In said wellbore fluid column which defines said plurality of sequentially transmitted acoustic transmission segments; and providing a control signal to said electrically-actuable wellbore tool when said digital circuit determines that said acoustic transmission defines said plurality of sequentially transmitted acoustic transmission segments.

According to another aspect of the present invention there Is provided a method of communicating in a weliba-re between a transmission node and a reception node, through a fluid column extending therebetween, comprising the method steps of:
providing a transmission apparatus at said transmission node which is in communication with said fluid column;
providing a reception apparatus at said receptibn node which includes:
(a) a sensor which detects acoustic pulses; and (b) an electronic circuit which examines said acoustic pulses one at a time to determine whether or not they correspond to at least one predefined actuation frequency;
utilizing said transmission apparatus to generate an acoustic transmission in said fluid column; and utilizing said reception apparatus to monitor said acoustic transmission during predefined reception intervals associated with said at least one predefined actuation frequency to (1) provide an actuation signal if said acoustic transmission is determined to correspond to said at least one actuation frequency and (2) reset said electronic circuit if said acoustic transmission Is determined to define some frequency other than said at least one predefined actuation frequency.

Accwding to yet another aspect of the pnesent inirention there Is provided a method of switching a remotely located wellbore tool between modes of operation, comprising:
providing (a) an electrically-actuable wellbore tool, (b) an acoustic pulse detection sensor, and (c) a frequency determination 10a circuit;
programming said frequency determination circuit to provide an actuation signal to said electrical ly-actua ble wellbore tool in response to a detection of a particular plurality of sequential acoustic transmission frequencies;
securing said electrically-actuable wellbore tool, said acoustic pulse detection sensor, and said frequency determiniition circuit to a tubular conduit string;
lowering said tubular conduit string within said wellbore to a selected welibore location;
providing a wellbore fluid column in contact with a portion of said tubular conduit but out of contact with said acoustic pulse detection sensor;
generating a plurality of acoustic pulse transniissions in said welibore fluid column;
utilizing said frequency determination circuit to switch said electrically-actuable wellbore tool between modes of operation, when it is determined that said acoustic transmissions match said particular plurality of sequential acoustic transmission frequencies;
and resetting said frequency determination circuit if it is determined that said acoustic pulse transmissions correspond to frequencies other than said particular plurality of sequential acoustic transmission.

According to still yet another aspect of the present invention there is provided a method of controillng a remotely located wellbore tool between modes of operation, comprising:
providing (a) an electrically-actuable wellbore tool, (b) an acoustic transmission sensor, (c) a digital circuit for continually examining, during monitoring operations, detected acoustic transmissions and providing a control signal if a detected acoustic transmission deflnes at least one predetermirred actuation frequency, and (d) an assignment member for assigning said at least one predetermined actuation frequency to said digital circuit;
said digital circuit including:
(i) a detection circuit communicatlvely coupled to said 10b acoustic transmission sensor for generating a pulse signal corresponding to each one of said acoustic transmissions;
(ii) a counter circuit communicatively coupled to said detection circuit for counting said pulse signal; and (111) an enabling circuit for selectively enabling said counter circuit, wherein said detection circuit, said counter circuit, and said enabling circuit cooperatively operate to cause the generation of said control signal;
assigning said at least one predetermined actuation frequency to said digital circuit;
securing said electrically-actuable welibore tool, said acoustic transmission sensor, and said digital circuit to a tubular conduit string;
lowering said tubular conduit string within said wellbore to a selected wellbore location;
providing a welibore fluid column in contact with a portion of said tubular conduit;
generating an acoustic transmission in said wellbore fluid column which defines said at least one predetermined actuation frequency; and providing a control signal to said electr+ically-actuable wellbore tool when said digital circuit determines that said acoustic transmission defines said at least one predetermined actuation frequency.

According to still yet another aspect of the present invention thene is provided an apparatus for communicating a control signal in a wellbore between a transmission node and a reception node, through a fluid column extending therebetween, comprising:
a transmission apparatus at said transmission node which is in communication with said fluid column, for generating an acoustic transmission having at least one acoustic transmission frequency;
a reception apparatus at said reception node w-hich includes:
(a) an electrically-actuable wellbore tool, (b) an acoustic transmission sensor, and (c) a digital circuit for continually examining, during monitoring operations, detected acoustic transmissions and providing a control signal if said acoustic 10c transmission defines at least one particular actuation frequency;
wherein, during a communication mode of operation:
(I) said transmission apparatus Is utilized to generate said acoustic transmission; and (ii) said reception apparatus is utilized to detect said acoustic transmission in said fluid coiumn; and a reception minimizer for minimizing reception sensitivity of said reception apparatus in a predefined manner by ehabling a pulse counting circuit at predetermined times corresponding to said at least one particular actuation frequency.

Aacording to stiY yet another aspect of the present ihvention tfiene is provided a method of communicating in a wellbore between a transmission node and a reception node, through a fluid column extending therebetween, comprising the steps oft providing a transmission apparatus at said traosmission node which is In communication with said fluid column including a controller for automatically generating at least one sequence of acoustic pulses which define at least one predeflned actuation frequency;
providing a reception apparatus at said receptiion node which includes:
(a) a sensor means which detects acoustic ptllses; and (b) means for examining said acoustic pulses one at a time with a pulse counting circuit to determine whether or not they correspond to said at least one predefined actuation frequency;
utilizing said transmission apparatus to generate an acoustic transmission in said fluid column; and utilizing said reception apparatus to monitor said acoustic transmission to provide an actuation signal if said acoustic transmission is determined to correspond to said' at least one predeflned actuation frequency.

According to still yet another aspect of the present hnrention there is provided a method of switching a remotely located weilbore tool between modes of operation, comprising:

1Od providing (a) an electrically-actuable wellbore tool, (b) an acoustic pulse detection sensor, and (c) a frequency determination circuit including a digital counter and a counter enabling circuit;
programming said frequency determination circuit to provide an actuation signal to said electricaily-actuable wlelibore tool in response to a detection of a particular acoustic transmission frequency;
securing said eiectrically-actuable wellbore tooi, said acoustic pulse detection sensor, and said frequency determination circuit to a tubular conduit string;
lowering said tubular conduit string within said wellbore to a selected wellbore location;
providing a welibore fluld column in contact with a portion of said tubular conduit;
providing a computer-controlled valve assembly;
generating an acoustic pulse transmission in said wellbore fluid column utilizing said computer-controlled valve assembly; and utilizing said counter enabling circuit to enable said digital counter of said frequency determination circuit to switch said electrically-actuable wellbore tool between modes of operation, when it is determined that said acoustic transmission matches said particular acoustic transmission frequency.

Additional object+ives, foatunes and advantages wili bo appanrnt in the written description which follows.

WO 96/24752 IG.18f PGTNS96101612 ry(~ V~~

BRIEF DESCRIPT[ON OFTHE DRAWINGS

The novel features believed characteristic of the invention are set forth in the appended claims. The invention itself, however, as well as a preferred mode of use, further objectives and advantages thereof, will best be understood by reference to the following detailed description of an itlustrative embodiment when read in conjunction with the accompanying drawings, wherein:

Figure 1 is a simplified and schematic view of one embodiment of the remote control apparstus of the present invention, which will be utiiized to present the broad concepts underlying the present invention;

Figure 2 is a simptified and schematic view of a pressure pulse generator, in accordance with one embodiment of the present invention, for generating "negative" pressure pulses;

Figure 3 Is a simplified and scFa3rnatic view of a unique pressure pulse generator, in accordance with another embodiment of the present invention, for generating "positive" acoustic puises;

Figures 4A and 48 are simplified one-quarter longitudinal seotion views of a pressure-transduc:er type reception apparatus, in accordance with one embodiment of the present invention, for detecting rapid changes in fluid pressure amplitude or acoustic pulses in a wellbore fluld column which serves as a communication channel;

Figures 6A and 58 are an electrical schematic depiction of components utilized to perform signal conditioning operations upon the output oF the pressure-transducer type reception apparatus depicted in Figures 4A and 48;

SUBSTITUTE SHEET (RULE 26) wo 96124752 I1187010 PCT/US96/01612 Figure 6 is a simplified partial longitudinal section views of a strain-o gage type reception apparatus; iri. accordance with another embodiment of the present inventlon, for sansing rapid changes in fluid preasure amplitude or acoustic pulses In the ftuid column which serves as a communication channel;

Figure 7 is an eiectrical schematic representation of the strain-gage type reception apparatus, which is depicted in i:igure 6, and inciudes a block diagram view of signal conditioning which Is performed upon the output of the strain-gage type reception apparatus when it is utilized to sense rapid changes in fluid pressure amplitude or acous#ic pulses in the fluid coiurun which serves as a communication channei;

Figures 8A and 8B are an electrical schemmtic of the pressure change detection circuit;

Figure 9 is a block diagram of the frequency detection circuit;

Figure 10 is a graphicai depictjon of the exsmpiary acoustjc transrnissions detected by the frequency detection circuit;

Figure 11 is a pictorial representetion of the overaA operation of a remote control sysbem which utiiizes the frequency detection circuit of Figure 9;
Figure 12 is a pictorial represen#ation of a programming terminal which is utiiized to program the processor of the reception portion the wellbore communication apparatus and Figures 13A, 138, and 13C are examples of the utilization of the display and keyboard to achieve bidirectionai cornmunication with the processor of the receptton apparatus;
Figure 14 is a simpii5ed block diagram representation of a magnetic Interface which faciiitates communcation between the programrrimg SUBSTI7UTE SHEET (RULE 26) wo 96124752 2197010 PCT1US96101612 terminal and the processor of the reception apparatus, without requiring a direct electrical connection;

Figure 15 is a simpiified partial longitudinal section view of the magnetic circuit component oFthe magnef3c Interface.

Figure 16 Is an electrical schematic of the programming terminal's magnetic communication interface;

Figure 17 is an eiectricai schematic and block diagram view of the electronic and processor components of the reception portion of the weiibore communication apparatus of the present invention;

Figures 18A and 18B are an electrical schematic of magnetic communication interface for the reception apparatus;

Figure 19 is an electrical schematic of the power-up circuit for the pressure change detection circuit;

Figure 20 is an electrical schematjc of a power-up circuit for the microprocessor oFthe reception apparatus;

Figures 21A and 21B are a flowchart representation of a user interface routine which allows communication between the reception apparatus and the programming terminal;

Figures 22A through 22D are a flowchart representation of an initialization routine;

Figures 23A through 23E are simpiified schematic views of the utiiization of the present invention to perform a cornpisbon opera6on;

SUBSTITUTE SHEET (RULE 26) Figure 24 is a longitudinal seotion view of the preferred expioding*
fastener end device oEthe present invention;

Fgures 25, and 26 depict a Keviar coupling end device which rnay be utilized with the remote control apparatus of the present Invention;
Figures 27A, 27B, 270, 27D, 28A, 28B, 28C, and 28D depict a sliding sleeve valve end device; and Figure 29 is a pictoriai representation of a dat processing yatem programmed in accordance with the flowcharts of Figures 30 through 33.

SUBSTtTUTE SHEET (RULE 26) WO 96/24752 PCTIQS%l01612 ~-i187010 DETAILED DESCRIPTION OF THE INVENTION

The detaifed description which follows is organized ander the following topic headings:
1. EXPLANATION OF ALTERNAYIVE EMBODIMENTS;
2. OVERVIEW OF THE SYSTEM;
3. THE NEGATIVE PRESSURE PULSE GENERATOR;
4. THE POSITIVE PRESSURE PULSE GENERATOR;
5. COMPUTER CONTROL OF THE POSITIVE PRESSURE PULSE
GENERATOR;
6. PRESSURE TRANSDUCER TYPE SENSOR;
7. THE STRAIN GAGE TYPE SENSOR;
8. THE PRESSURE CHANGE DETECTION CIRCUIT;
9. FREQUENCY DETERMINATION CIRCUIT;

10. THE PROGRAMMiNGTERMINAL;

11. OVERVIEW OFTHE RECEPTION APPARATUS;
't2 THE MAGNETIC lNTERFACETERAAINALOFTHE PROGRAMMING UNIT;
13. THE MICROPROCESSOR CIRCUIT;
14. THE MAGNETIC COMMUNICATION INTERFACE OF THE RECEPTION
APPARATUS;
15. THE POWER-UP CIRCUIT FOR PRESSURE CHANGE DETECTION
CIRCUIT;
16. THE POWER-UP CIRCUIT FOR THE MICROPROCESSOR;
17. THE COMPUTER PROGRAM;
'18. COMPLETION OPERATIONS;
19. EXPLODING FASTENER END DEVICE;
20. THE KEVLAR COUPUNG END DEVICE; and 21. THE SLIDING SLEEVE END DEVICE

SUBSTITUTE SHEET (RULE 26) W0 961?.4752 Z I b ~ ~ 1 ~ PCT1US96/01612 1, DCPLANATION OF ALTERNATIVe EMBOOIMENT3: in the presentO
invention, several aftennatives are provided.

There are alternative techniques for generating a remobe control signal at a transmission node, including: a"nega#ive pulse technique"
which utilizes a conventional fluid pump and a conventional valve to generate a plurality of "negative" pressure pulses which constitute a control signal, and a"positive puise technique" which utilizes a unique valving apparatus to generate a plurality of "positive" accustic pulses which constitute a con#rol signal.

There are also alternative techniques for sensing the reniote control signal at a remotely located reception node, including: a"pressure transducer tochnique" which utilizes a pressure transducer which is maintained out-0f-contact with wellbore fluids but which nonetheless detects the remote control signal in a wellbore fluid column through changes in eiastic defonmation of a rigid structnral component, and a "=strain gage technique" which utilizes a conventional atrain gage bridge to detect directly a sequence of circunrfereni3ai eiastic defoimations of a rfgid structural component, such as a mandrel.

There are also several difFerent embodiments of electricaliy,actuable we[Ibore tools, including: an eiectrically-fiagrnented pin member and a valve assembly.
2. OVERVIEW OFTHE SYSTEM: FiBure 9 is a simplified and schematic view of the wellbore communication apparatLS 11 of the embodiment for the positive pulse technique. As is shown, communication apparatus 11 is disposed within wellbore 49. Considered broadly, wellbore communication apparatus 11 is utilized to communicate remote control signals within any fluid column, but in the preferred embodiment fiuid column 55, from transmission apparatus 51 which is focated at transmission node 45 to reception apparatõs 53 whIch Is located at reception node 47 within SUBSTITUTE SHEE'!'(RUl.E.Z6) . ~. ,,. . , . .,. .
Wo 46/24752 PGT/US96I111612 wellbore 49. In this embodiment, reception apparatus 53 Is located within wellbore 49 on tubular conduit stricig 13 which is composed of a plurality af tubular members, such as tubular member 17 and tubular member 19, which are threaded together at conventianal pin and box threaded couplings. In the view of Figure 1, tubular conduit string 13 is greatly simplified; in acbual practice, typically, several hundred tubular conduit members are coupled together to define tubular conduit string 13 which extends from the welihead to a remote wellbore iocation, possibly several thousand feet below the earth's surfqce. Central bore 15 ia defined within tubular conduit string 13. As is shoWn In Figure 1, tubular conduit string 13 may be concentric with other wellbore tubuiars, such aa casing 24 which is utilized to prevent the washout or deterioration oFformation 23, and to allow for the selective communication of oil, gas, and formation water with wellbore 49 through perforations within casing 21 which are provided at selected locations (and which are not shown in this figure).

Wellbore communication apparatus 11 includes sensor assembly 25 for detecting changes In the pressure of fluid column 55 within central bore 15, drive mechanism 27 which I. eieatrically-~actuated by sensa' aasembty 25, and toot mechanism 29 which achieves an engineering objective within the welibore in response to interaction with drive mechanism 27. Viewed broadiy, drive mechanism 27 and tool mechanism 29 comprise an electrically-actuated wellbore tool 31 which may be selectively switched between operating nwdes or stabes in resporme to electrical signals received from sensor assembly 25. Preferably, sensor assembly 25 includes a microprocessor which is utilized to record either one or two frequency values which are uniquely associated with a particuiar wellbore tool. This allows wellbore communication apparaks 11 to be utiti~ed In an engineering environment wherein a plurality of eiectricaliy-actuatred welibore tools are provided at selected locations within tubular conduit string 13, each of which is responsive to one or two frequency values and which is thus independently operable.

SUBSTITUTE SHEET (RULE 26) - ~.

Sensor assembly 25 is partisiiy housed within mandref member 590 which comprises a rigid structural component with an exterior surface 61 which is in direct contact with fluid: cotumn 55, and Interior surface 63 which is not in direct contact or communic=ation with fluid column 55. As is shown in Figure 1, mandrel member 59 cooperates with adjoining tubular members to define central bore 25 within tubular condui# sbing 13. In the preferred embodiment, sensor assembiy 25 Is utfiined to detect eiastjc deformation of mandrel member 59 In response to changes in pressure amplitude of fluid column 55, and in particular to detect changes in the eiastic deformation of mandrel member 59. In the preferred embodiment, mandrel member 59 is formed of 4140 steei, which has a moduius aP
elasticity of 30,000,000 pounds per square inch, and a Poisson ratio of 0.3.
Also, in the preferred embodiment, the portion of mandrel member 59 which is adjacent reception apparatus 53 is cylindrical in shape, having an outer diameter of 5.5 inches, and an inner diameter of 4.67 inches. As can be seen from Figure 1, mandrel member 59 serves to form a substantjaiiy imperforate conduit wall within tubular member 19 of tubular conduit string 43.

3. THE NEGATIVE PRESSURE PULSE GENERATOR: In the particwar embodiment which employs the negatjve puise technique, wellbore communication apparaiu!s 11 inciudes transmission apparatus 51 which is shown in Figure 1 as being focated at the wellhead, which for purposes of discussion can be considered to be a"b=snsmission node" 45. Also, as is shown in Figure 1, reception apparatus 53 Is disWly located from transmission apparatus 51, and In particular is shown as being located at reception node 47 within wellbore 49. Pressure waves of one or more predefined frequencies are communicated from tranamission apparatus 51 for detection by reception apparatus 53. Receoon apparatus 63 is ulfliz,ed to detect rapid changes in amplitude of the pressure exerted by fiuid column 55 upon ntandrei member 59, while maintaining sensor assembiy 25 out of direct, or indireci, contact or communication with fluid column 55.
The amplitude, and rate of change of the amplitude, of fluid cokunn 55 is SUHSTlT'UTE SHEET (RULE 26) manipulated with respect to time by a human operator who operates and monitors fluid pump 37, which communicates through valve assembly 35 with fluid column 55. Pressure gage 39 is utilized to monitor the pressure of fluid column 55, while amplitude control 41 is utilized by a human operator to urge fluid column 55 toward a preselected pressure amplitude, or to maintain a particular amplitude. Timer 43 is also utilized by a human operator to monitor time inteivais.

In this embodiment, the human operator manually fiest operates valve assembly 35, which is shown in simplified form in Figure 1, to allow for the pressurization of fluid column 55 by pump 37, and then allows the selective venting of high pressure fluid from central bore 16 to annulus 57, or more preferably to a reservoir, which Is maintained at a lower pressure. After pressuriAng fluid column 55 a predetermined amount, the human operator may vent fluid from fluid column 55 through valve assembly 35 to such a reservoir. This process is repeated a certsin number of times in a sequence which defines one or two transmission frequencies. These rapid changes in the amplitude of the pressure of fluid column 55 affect the elastic deformation of mandrel member 59 of reception apparatus 53 in a manner, which will be discussed herebelow, which is detected by sensor assembly 25. Timer 43 is utiiized to maintain timing for the message segments to help the human operator obtain the one or two transmission frequencies uniquely associated with any one of particular wellbore tool.

In the preferred embodiment, pump 37 should have sufficient capacity to provide fluid pressurized to a selecteble amount in the range of zero pounds per square inch to twenty thousand pounds per square inch, and should preferably have an output capacity of between six to twenty gallons per minute. In its most rudimentary form, timer 43 may comprise a standard clock which is not coordinatsd in operation with pump 37. In the preferred embodiment, valve assembly 35 is a conventional one-quarter turn cock valve which is utilized at wellheads. In atternative embodiments, the operation of timer 43, amplitude control 41, pump 37, pressure gage 39, SUBSTtTUTE SHEET (RULE 26) WO 96/24752 PCT/US9"1612 and valve assembEy 35 may be coordinated and subjected to comput,eris control to render wellbore communication apparatus 11 easier to utiiize.
Figure 2 is a more detailed view of the pressure pulse generator which can impiement the "negative pulse technique". As Is shown, valves 35, 36 are utilized to allow the selective comnwnication of rig pump 37 and reservoir 38 with fluid cofumn 55 disposed within tubufar conduit string 13.
As is shown, valve 35 Is disposed adjacent weithead 40. As identified above, valve 35 comprises a one-quarter turn cock valve, which may be physically operated by a human operator at the weilhead. Valve 38 is also manually-operable to allow the seiective comrnunicaflon of conduits 44, 46 with conduit 42 which extends between vaive 35 and valve 36. Conduit 44 extends between valve 36 and reservoir 38, while conduit 46 extends between valve 36 and rig pump 37.

When the operator desires to increase the preasure of fluid column 55 within tubuiar conduit string 13, vaive 35 and valve 36 are manually operated to allow the passage of fluid from rig pump 37 to fluid column 55 by passage through conduit 46, valve 36, conduit 42, valve 35, and weiihead 40. As Is shown in Figure 2, rig pump 37 draws fluid from reservoir 38. When a sufficient fluid pressure ampiitude is obtained within fluid column 55, as determined by readings of pressure gage 39, valve 35 is manually closed. When the operator desires to transmit an acoust3c puise, valve 36 is manually operated to allow the communication of fluid from fluid column 55 to reservoir 38, by aiiowing passage from conduit 42 to conduit 44. Then, the operator manually operates valve 35 in a predetermined sequence to create a series of rapid changes in fluid pressure amplitude which define a particular predefined frequency, as will be discussed In greater detail herebeiow. in this negative pressure pulse technique of generating coded message segments, it is the rapid decrease in fluid pressure ampiitiide of fluid column 55 which comprises the acoustic pulse.
The volume of fluid evacuated from fluid column 55 to reservoir 38 need not be great in order to create a plurality of sequentfai rapid decreases in pressure amplitude, and the absolute volume of fluid within fluid column 55 SUBSTITUTE SHEET (RULE 26) need not be attered to a great extent in order to create coded messages.
Utilizing an altsrnative pressure pulse generator, a particular transmission frequency can be generated from a pturaiity of rapid, and momentary, increases in the fluid pressure amplitude of fluid column 55.

4.- THE POSITIVE PRESSURE PULSE GENERATOR: An apparatus which can be utiiized to perform the alternative positive pulse transmission technique is depicted in Figure S. 1n this view, pressure pulse generator 175 is shown in longitudinal section view, and the remainder of the components which interact therewith are depicted in simplified and block diagram form. As is shown, pressure puise generator 175 includes cylindrical housing 176, which is preferably approximately eighteen and one-haif inches long, having an internal diameter of just under twelve inches. Cylindrical housing 176 is threaded at both ends for engaging end caps 177, 178. O;ing seals 181, 182 are provided at the interface of end caps 177, 178 and the interior surface of cylindrical housing 176.
Preferabty, a disk-shaped piston 179 is disposed within cyiindrical housing 176, and includes 0-ring 180 to provide for a dynamic sealing engagement with the interior bore of cylindrical housing 176. In the preferred embodiment, end caps 177.178 include bores 183, 185, which preferably have a diameter oF approximately 0.17 inches, and a length of three incHes_ Bore 183 is utilized to allow pressure gage 184 to monitor the pressure within compartment 197 which is defined between end cap 177 and disk-shaped piston 179. Bore 185 is utilized to allow the selective communication between compartment 198 and four-way valve 188.

In the preferred embodiment, compartment 197 Is filled with an inert gas. The compartment is air-Ught, and leak-free. Displacement of disk-shaped piston 179 toward end cap 177 will cause an increase in pressure of the inert gas contained within compartrnent 197, which is detected by pressure gage 184. In the preferred embodiment, compartment 198 is filled with a liquid, such as water, which is propelled outward through bore 185 if disk-shaped piston 179 Is urged right-ward toward end cap 178. In SUBSTiTUTE SHEET (RULE 26) WO 96/24752 PCT/US96l01612 the preferred embodiment, end cap 178 includes conical region 199 whics defines an angle 198 of thirty-,dporees, and a diameter at its base of ten inches. This conical-sHape'r! aurface 199 serves to direct fluid from compartment 198 into bore 185. Bore 185 communicates through hose 187 to four-way valve 188. In the preferred embodiment, hflse 187 comprises a five foot length of rubber hose, which is rated to tfuee thousand, five hundred pounds per square inch, and which Is idetrtNied by Model No. SS-8R8-PM8-PM8-60. Ruid pump 191 communicates with four-way valve 188 through hose 190, which is identical to hose 187. Addtionaiiy, hose 192 is ufllized to communicate fluid between four-way valve 188 and fluid column 55 (of Figure 1). Four-way valve 188 also communicates with bleed port 189.

Four-way valve 188 includes pump valve 193, pressure puise generator valve 194, bleed valve 195, and well valve 196. Well valve 196 allows selective communication of fluid between four-way valve 188 and hose 192, which is preferably a rubber hose, which is fifty feet long, and which is identified by Model No. SS-8R8-PM8-PM8400.

In the preferred embodiment, pressure puise generator 175 is utilized to discharge a small amount of fluid, such as water or weiibore fluid, Into fluid column 55 (of Figure 1) which produces a rapid pressure change which may be detected at substantia! distances within the weiibore, but which does not substantially impact the absolute volume of the fluid contained within fluid column 55. Preferabiy, compartrnent 198 is configured in size to allow the discharge of between one-half gallon to one gallon af fluid, an infinitesimal amount of fluid considering that fluid column 55 may be thousands of feet in length. Pressure pulse generator 175 may be utilized in a manner to provide a plurality of rapid preasure puises, each pulse occurring at a preestablished time, to create a an acoustic transmission having a particular predefined frequency which may be detected at reception node 47 by reception apparatus 53 (of Fgure 1).

SUBSTITU'!'E SHEET (RULE 26) WO 96114752 PCTI[J$96/01612 The low volume pressure pulses are generatsd utilizing pressure pulse generator 175 In the fnllowing manner.

1. pnassure pulse generator vah-e 194 af four-+way valve 188 Is closed to prevent communication of fluids into compartment 198;
2. bleed valve 195 is opened to allow communication of fluid between four-way valve 188 and bleed port 189;
3. pump valve 193 of four-way valve 188 is closed to prevent communication between fluid pump 191 and four-way valve 488; , 4. well valve 196 is opened to allow communication between fluid column 55 and four-way valve 188;
5. the rig pump (not depicted) is then uUiized to compietely fill central bore 15 (of Figure 1) to provide a fluid column which extends from the wellhead (not depicted) downward through the welibore conduit string which defines central bore 15 (of Figure 1);
6. bleed port 89 is then monitored by a human operator until fluid is dote 7. operation of the rig pump Is then terminabed;
8. bleed port 195 is then closed to prevent fluid from escaping through bleed port 189;
9. well valve 196 is then ciosed to prevent fluid from passing between four-way vaive 188 and hose 192;
10. pump valve 193 is opened to aikyer the communication of fluid from pump 191 to four-way valve 188;
11. pressure puise generaior valve 194 is opened to allow the communication of fluid from four-way vaive 188 to compartment 198 through hose 187;

12. pump 191 is then utilized to pump fluid, such as water or wellbore fluid, from reservoir 202, through four-way valve 188, through hose 187, to fii1 compartment 198 with fludd, causing the leftward displacement or disk-shaped pist,on 179, and corresponding oompression of the inert gas contained within compartment 197;

SUBSTrrUTE SHEET (RULE 26) WO 96/24752 PGT![3$96151612

13. gage 184 is monitored to detect the compression of the inert ~
gas to one thousand pounds per square inch (1,000 p.s.i.) of force;

14. upon obtaining a force of one thousand pounds per square inch within compartment 197, the operation of pump 191 is discontinued;
15_ pump valve 193 is then dased to prevent the communication of fluid between four-way vaive 188 and pump 191;
16. well valve 196 is then opened, aAowing the cornpreased inert gas within chamber 197 to urge disk-shaped piston 180 rightward to discharge fldid contained within compartment 198 through hose 187, through four-uvay vaive 188, and into fluid column 55 of Figure 1.

The execution of these operating steps generates a low voiume, low frequency pressure pulse, with a volume oF appraximaWy one-haif to one gallon of fluid, and a fundamental frequency of approximateiy one to two Hertz. The pressure pulse is essenUely a sbep function of fixed (s#rort) duration. Hose 187, four-way valve 188, and hose 192 serve to attsnuate the pressure pulse and ansure that oniy the main harmonic of the pressur+e pulse is Introduced into fluid column 55 (of Figure 1). However, the pulse does not substantiaiiy change the absobe volume of fluid column 55 (oF
Figure 1). The low fraquency (one to two Hertz) pressure pulse travels downward within fluid column 55 of Figure 1 to reception node 47 where It Is detected by reception apparatus 53.

A comparison of the pressure pulse generating techniques of Figures I and 2 reveal that the technique of Figure 1 operates by providing a brief negative pressure puise by venting fluid from fluid column 55, while pressure pulse generator 175 is utjiized to create a"positive" pressure pulse by introducing fluid into fluid column 55.
Viewed broadly, the positjve pn~ssure pulse generator Is utiiiz,ed to generate a series of pressure puises in a fluid column, each of which creates a temporary and transient change in fluid pressure amplitude in the SUBS'TTTUTE SHEET (RULE 26) WO 96/24752 2187010 PCTILfS96101612 ~ coiumn which travels the length of a column, but which does not substantially change the absdute vdume of a fluid column. The known volume of fluid which is discharged frorn the pcsitjve pressure pulse generat,or must be introduced tft the fluid column at a very rapid rate in order to ensure that the pressure "pulses" have the above-identified attributes. For optimal perl:ormance, the fluid which is discharged from the positive pressure pulse generator into the fluid column should be introduced at or about a velocity which approximates the velocity of sound within the particular transmission medium. OF course, the velocity of sound varies with the viscosity of the transmission medium. A rather clean fluid, such as watsr, has one transmission velocity for sound, while a more viscous fluid, such as water containing numerous impurities and additives, will have a different transmission velocity for sound. For all practical purposes, the pressure pulses generated by the positive pressure pulse generator are "acoustic" waves which travel the length of the fluid column and have only a temporary and transient impact on the fluid pressure amplitude at any particular iocation within the fluid column. It Is the impulse nature of the fluid pressure pulses generated by ttne positive pressure pulse generator which allow for the transmission of pulses over significant distances, without requiring a significant change in the absolute volume of the fluid contained within the fluid column.

5. COMPUTER CONTROL OF THE POStTIVE PRESSURE PULSE
GENERATOR: With reference now to the figures and in particular with reference to Figure 29, there is depicted a pictorial representetion of data processing system 3010 which may be programmed in accordance with the present invention to control and monitor the poaitive pressure pulse generator valve. As may be seen, data processing system 3010 includes processor 3012 which prefenabiy includes a graphics processor, memory device and central processor (nat shown). Coupled to processor 3012 is video display 3014 which may be implemented utiiizing either a color or monochromatic monitor, in a manner well known in the art. Also coupled to processor 3012 is keyboard 3016. Keyboard 3016 preferably cornprisea a SUBSTITUTE SHEET (RULE 26) WO 96124752 21870{0 PCE'/US96/01612 standard computer keyboard which is coupled to the procesaor by meanse of cable 3018.

Also coupled to processor 3012 is a graphical pointina device, such 6 as mouse 3020. Mouse 3020 is coupled to processor 3012, in a manner well known in the art, via cable 3022. As is shown, mouse 3020 may include left button 3024, and right button 3028, each of which may be depressed, or "clicked", to provide command and control signals to data processing system 3010. While the discloeed embodiment of the present invention utilizes a mouse, those skilled in the art wiil appreciate that any graphical pointing device such as a light pen or touch sensitive screen may be utilized to implement the method and apparatus of the pnesent invention. Upon reference to the foregoing, those skilled in the art wiil appreciate that data processing system 3010 may be implemented utilizing a so-called personal computer, such as the Model 80 PS12 computer rnanuFactured by international Business Machines Corporation of Armonk, New York, or any other commercially available data processing system.

In the preferred embodiment, pressure pulse genenator 175 is placed under computer control to discharge a small amount of flvid, such as water or wellbore fluid, into fluid column 55 (of Figure 1) which produces a rapid pressure change which may be detected at substantial clatances within the wetibore, but which does not substantially impact the absolute volume of the fluid contained within fluid column 55. Preferably, compartrnent 198 is configured in size to allow the discharge of between one-half gallon to one gallon of fluid, an irtfinitesima! amount of fluid considering that fluid column 55 may be thousands of feet in length. Pressure pulse generator 175 may be automatically achmted in a manner to provide a plurality of rapid pressure pulses, each pulse occurrin8 at a preestablished time, to create an acoustic transmission having a particular predefined frequency which may be detected at reception node 47 by reception apparatus 53 (of Figure 1).

SUBSTITUTE SHEET (RULE 26) - ..., ....
WO 96124752 PCTlIIS96101612 40 The iow-voiume pressure pulses are generated utilizing pressure pulse generator 9?5 under the controi of a computer program with program instructions being executed by data processing system 3010 in the following manner.
1. pnessurs.. puise generator vahre 194 of four-way valve 188 is electrically actuated to be closed to prevent communication of fluids into compartment 198;
2. bleed valve 195 is electricaily ac#uated to be opened to allow ccmmunication of fluid between four-way vaive 188 and bleed port 189;
S. pump valve 193 of four-way valve 188 is electricaliy actuated to be closed to prevent communication between fluid pump 191 and four-way valve 188;
4. well valve 196 is electrically actuated to be opened to allow communication between fltrid column 55 and four-way valve 188;
5. a dedicated pump or the rig pump (not depicted) is then electrically actuated to completely ftU central bore 15 (of Figure 1) to provide a fluid coiumn which extends from the weiihead (not depicted) downward through the welibore conduit atring which defines central bore 95 (of Figure 1);
6. bleed port 89 is then monitored by an eiec#rioal sensor until fluid is detected as flowing outward therefrom, an incOcation that central bore 15 is completely full of fluid, and that hose 192 Is likewise completely full oFfluid and a signal is providad to data processing sys6Qm 3010;
7. operation af the dedicated pump or the rig pump is then termitiated by a command from data processing system 3010;
8. bleed port 195 Is then etectricaily actuated to be closed to prevent fluid from escaping ttrough bleed port 189;
9. welt valve 196 is then electricaiiy actuated to be closed to prevent fluid from passing between four-way vaive 188 and hose 192;

SUBSTITUT6 SHEET (RULE 26) 10. pump valve 193 is electrically aa#ua#ed to be opened to aiiow=
the communic.ation of fluid froan pump 191 to four-way valve 188;
11. pressure pulse generator valve 194 is electrically actuated to be opened to allow the comrnunication af;fuid from four-way valve 188 to compartment 198 through hose 187=
12. pump 191 is then electrically actuated to be utiiized to pump fluid, such as water or weiibore fluid, from reservoir 202, through four-way valve 188, through hose 187, to fill compartment 198 with fluid, causing the leftward displacement of disk-shaped pist,on 179, and corresponding compression af the inert gas contained within compartment 197;
13. gage 184 provides an eiectricai signal to data processing system 3010 which is monit,ored to detect the compression of the inert gas to one thousand pounds per square inch (1,000 p.s.i.) of force;
14. upon obtaining a force of one thousand pounds per square inch within compartment 197, the operaEion of pump 191 is discontinued;

15. pump valve 193 is then electrically actuated to be ctosed to prevent the communication of ftuid between four-way valve 188 and pump 191;

16. well valve 196 is then electrically actuated to be opened, allowing the compressed inert gas within chamber 197 to urge disk-shaped piston 180 rightward to discharge fluid contidned within compartment 198 through hose 187, through four-way valve 188, and into fluid colurnn 55 oF
Figure 1.

The execution of these operating steps automaticaiiy generates a low volume, low frequency pressure pulse, with a volume of approximateiy one-hatf to one gallon of fluid, and a fundamental frequency of approximately one to two Hertz. The pressure pulse is essenUaiiy a atep function of fixed (short) duration. Hose 187, four-way vaive 188, and hose 192 serve to attenuate the pressure pulse and ensure that only the main harmonic of the pressure pulse is introduced into fluid column 55 (of Figure 1). However, SUBSTITUTE SHEET (RULE 26) PC.TlUS96ro1stz WO 96124752 21,87010 the pulse does not substantially change the absolute volume of fluid column 55 (of Figure 1). The low frequency (one to two Hertz) pressure pulse travels downward within fluid column 55 of Figure 1 to reception node 47 where it Is detected by reception apparatus 53.
The steps setforth above are perforrned by the execution of program instructions by data processing syst,em 3010 in accordance with the flowchart representation of Figure 30. The process begins at software block 3030, wherein the routine Is called for processing. Next, in accordance with software block 3032, data processing system 3010 closes compartment 198 of the pressure pulse generator 175. This activiiy corresponds to step number one enumerated above. Then, in accordance with software block 3034, data processing system 3010 filis the fluid pathway between the weUbore fluid column and compartment 198 of pressure pulse generator 175. This software action corresponds to the steps numbered two through nine which are set forth above. Then, in accordance with software block 3036, data proceasing system 3010 pressure charges fluid in the compartment 198 of pressure pulse generator 175. This software activity corresponds to the steps numbered ten through fifteen which are set forth above. Then, in accordance with software block 3038, data processing system 3010 propels a fluid slug into the wellbore fluid column. This corresponds to st.ep number sixteen which is set forth above. The process ends at software block 3040.

In the preferred embodiment of the present invention, the computer program includes a subroutine for defining the one or more acoustic actuation frequencies which can be utilized to remotsfy control subsurface weElbore equipment As will be explained in greater deWi, each remotely actuable wellbore tool is responsive to either one or two acoustic transmissions, each defining an actuation frequency. In accordance with the present invention, data processing syatem 3010 may be utilized to repeatedly actuate the pressure pulse generat,or 175 in a pattern which defines the one or two partjcuiar acoustic transmission frequencies, and SUBSTIZUTE SHEET (RULE 26) WO 96P24752 2187.010 PCT/LTS96I01612 thus which repeatedly performa the soitware operations depicted anci*
described in connection with FlguM 30. Figure 31 is a flowchart representation of the programMing operstions, which start at software block 3042. The operations continue at software btock 3044, wherein data processing system 3010 queries a user to define the achsiion freqcmncies, preferably by keyboard inpuL Next, in accordance with software block 3046, data processing system 3010 receives the user input, and in accordance with soflware block 3048, confirms this selectjon by engaging the user in a verification dalog. Finally, the operator selections are recorded in memory In accordance with software block 3050, and the routine ends at software block 3052.

In one particuiar embodiment of the present invention, data processing system 3010 may be utjlized In oombination with pressure sensors to monitor and record the operating performance of pressure pulse generator 175, and the software afieps of Figure 30 which are utilized to consecutively actuate the pressure pulse generator 175. Preferably, one or more acoustic transmission quaii6es or attributes are monitored during actuation of pressure puise generator 175. These attributes may Include, but are not limited to, the following: pressure pulse amplitude, pressure puise duration, pressure puise velocity, and the exact time the presaure pulse was applied to the wellbore fluid column. The operator may interact with data processing system 3010 prior to achiation of pressure puise generator 175 to define one or more of these attributes or crifieria for proper operations. For example, the operator may establish a minimum pressure pulse amplitude, below the acoustic pulse which is considered to be unacceptable. Aiternativaely, the operator may define acoustic pulse velocity thresholds which must be exoeeded for proper operation.
Alternativeiy, the operator may define a pressure puise duration which must be satisfied for proper operation. These attributes rnsy be defined and quantified through experimental and controiled actuation of pressure pulse generator 175 in a variety of weilbore types and georttetries. Provided a sufficiently large sampling is obtainsd, a statietically significant criterion SUBSTiTUTF SHEET (RULE 26) WO 96124752 PClYUS96101612 may be estabiished for particular types of wells and operating conditions (such as aitibude, temperature, and the physical properties aaF the weiibore fluid column). Pmferabiy, a variety of opemting crit,eria are established for different well types and operating conditions. If rema6e actuation is desired in extrerneiy cold operations in particular well configurations and geometries, the thresholds which abide for other different wells and operating conditions may not apply. Therefore, a routine is established which allows the operator to independenUy set the operating thresholds for pressure pulse generaftr 175. This routine is depicted in broad flowchart form in Figure 32. The process : starts at software block 3054, and continues at software block 3056, wherein data processing system 3010 queries the user for operating criteria for acoustic transmissians, for the particuiar environment and well iype. Then, in accordance with software block 3058, data processing system 3010 records the operator criteria, and the process ends in software block 3060.

The overall operation of computer controi of pressure puise generator 175 is depicted in flowchart form in Figure 33. The process sbals at sottware bkmk 3062, continues at software block 3064, wherein data processing system 3010 calls the programming routine to allow programming of the acoustic transmission frequencies. Next, in accordance with software biock 3066, data processing system 3010 continualiy monitors for an actuabion command which is received from either operator input. or from anathar programmed subroutine. Once an actuation command is received, the process continues at software block 3068, wherein a counter is initlaiized. In accordance with software block 3070, data processing systam 3010 perfams the actuation radine of Figure 30. Then, a counter is increment,sd in acca+dance with software block 3072. Next, a monit,or routine is cxdied which analyzes the ampl'itade, duration, andlor velocity of the aaoustic transmissions emanating from pressure puise generator 175, and cornpares them to the operator established operating criteria. In the event that one or more operating criteria are violated, the operat,or is alerted through prompts provided by SUBSTItUTE SHEET (RULE 26) data processing sysbem 3010. Nextõ in accordance with software block 3076, data processing systam 3010 examines the count to determine whether a predefined number of actuatjon operatjons have been completed; if not, the process returns to svftware block 3070; if so, the process continues at soflware block 307$ tiy ending the routine.

6. PRESStJRE"TRANSOUCER TYPE ENSOR: Figures 4A and 4B are detaii views of reception apparatus 53 of welJbore communication apparatus 11, depicted in fragmentary iongiWdinal section view, and in simpi'ified fonm which may be utiiized with either the negative pressure pulse generation technique or the positive pressure pulse generatjon technique, but which is depicted and described as used in conjunction with the negative pressure pulse generation tecimique. As is shawn, mandrel member 59 helps define central bore 15 in the region of reception apparatus 53. Central axis 65 of fluid column 55 is depictad to provide orientation in theae figures.

Figure 4A depicts reception apparatus 53 when the pressure of fluid column 55 equals the pressure wittin sensor cavity 67, which is preferably maintained at atmospheric pressure. in conbstist, Figure 48 depicts, in exaggereted form, reception apparatus 53, when the pr+essure of fluid column 55 is far greater than that af sensor cavity 67. As is shown, mandrel member 59 is eiastically deformed radially outward from central axis 65 by the pressure differential between fluid column 55 and sensor cavity 67. As is shown in both Figures 4A and 4B, reception apparatus 53 includes sensor cavity 67 which is defined between mandrei member 59, outer mandrel 79, and end pieces 75, 77 which are rin"haped, and which inciude 0-ring seals 81, 83 to provide a fluid-tight seal at the interface of end piece 75 with mandrel member 59 and outer mandrel 79, and end piece 77 with mandrel member 59 and outer mandrel 79. As I. shown, circuit board 69 is disposed within sensor cavity 67. Pressure sensor 71 Is coupled to circuit board 69. The electrical components which are d=isposed within sensor cavity 67 will be discussed in greater detail below. In the preferred embodiment, sensor cavity 67 is completely filled with a SUBSTiTUTE SHEET (RULE 26) WO 96/24752 2187010 rcrnrs96ro1612 ,~ substantislly incompressible fluid 73. When the rigid mandrei member S9 is eiasticaily deformed by the pressure ditferential between fluid column 55 and sensor cavity 67, pr+easure is applied to pressure sensor 71 through the substantiaiiy incompressibie fluid 73.

In this embodiment, pump 37 (of Figure 1) and valve assembly 35 (of Figure 1) are u5lized to create and maintain the pressure diifereniial between fluid column 55 and senaor cavity 67. In this embodiment, it is desirable to utilize pump 37 to create a pressure differential between fluid column 55 and sensor cavity 67 which is in the range of 1 pound per square Inch to 10 pounds per square Inch. Once this pressure diRerentiall Is obtained, valve assembly 35 ts utilized to selectively vent fluid irom fluid column 55 to a reservoir at the surface, or more-rarely to annulus 57, In an operator-controlled manner to provide a plurality of sequential rapid changes in the pressure ampiitvde of fluid cdumn 55 which result in the gradual return of mandrel member 59 from the position shown in Figure 4B
to the position shown in Figure 4A. Therefore, mandrel member 59 is maximally elastically deformed at the beginning of a barwmission of the remote conbvi signal, and returns eventually, to the undeformed condition shown in Figure 4A. Of course, Figure 48 is an exaggerated depiction of the elastic deformation of mandrel member 59. Keep in mind that mandrel member 59 is iamed of 4140 steel, and has a thickness of approximately 0.4 inches, so the acdyual elastic deformation vf this rigid structural component wiii be slight In the pre#erred embodiment, mandrel member 59 is elastically defonnad in the range of 0.001 inches to 0.003 inches, and returns to its undeformed condition as the presswe diffferential between fluid column 55 and sensor cavity 67 Is reduced.

The eiastic detormation of mandrel member 59 reduces the volume of sensor cavity 6T which is filled with substantially incornpressibie fluid 73, such as a light oil. An increase in the volume of sensr cavity 67 results in a decrease In pressure applied through subgtantiaily inconspressible fluid 73 to pressure sensor 71. A decrease in the volume of sensor cavity 67 resuits SUBSTITUTE SHEET (RULE 26) wo ~752 21 87410 PCr/Us96101612 in an incresse in pressure applied through substantially incompressibieo fluid 73 to pressure sensor 71. In tbis embodiment, pressure sensor 71 comprises a Model No. SXOIO pressure traneducer, manufaatured by SenSym of Califarnia Also, In this embodiment, the substantially incornpressible fluid comprises Silicone Qil,' or any similar nonc:onrosive, electricaily-inert fluid.

In this embodiment it Is not the pressure amplitude of fluid column 55 which is important; rather, it Is the change in the pressure amplitude which is detected by receiver apparatus 63, ensuring that the receiver apparatus 53 is substanl3ally unaffected by slow changes in the anmoititde of the pressure exert,ed by fluid column 55 an mandrel member 59. This is a desirable resuit, since many convenfiional wellbore opera6ons require that the pressure within fluid column 55 be altered with respect to time to achieve sane other engineering objectives. A pressure threshold is provided, below which recepti on apparatus 53 is substantially insensitivs to accidental, ambient, or unintentioned dmnges in the pnessure of fhdd column 55, so the accidentai creation of a contrVi signal is unlikely.

Figures 5A and 5B are an electrical schematic depiction of comporeents utilImd to perform signal conditioning operations upon the output oF pressure sensor 71 . Pressure sensor 71 develops as an output a differential voltage. The voltage at one output fierminai Is suppiied through the lntegrating R-C circuit oanposed vF capacifor 78 and reaistor 86 to the non-inverting input of operational amplifler 82, while the voltage at the other ouoxt terminsl of pressure bansducer 71 is supplied through inftgrating R-C circuit composed of capacitor 80 and resistor 88 to the inverting input of operational amp pffier 82. Feedbacic resistnr 80 is supplied between the inverting input of operational amplifier 82 and the output of operational amplifier 82. In this configuration, operational amplirw 82 is performing the operation of an afternating current, differentisl voftage amplifier. The gain of this differential voltage amplifier is estabiished by the resistor value selected for resistors 88, 90. Preferably a gain of 500 is established by this SUBSTITUTE SHEET (RULE 26) circuit The output of operational ampiifier 82 is supplied to the non-inverting input of operational amplifier 92, which is operated as a buffer.
The output of operational ampiifier 92 is supplied through resistor 94 to the non-inverting input of operationai amplifier 98. Capac.itor 96 is coupled between the non-inverting input of operational amplifier 98 and ground, while resistor 100 is coupled betwaen the inverting input of operationel ampPifier 98 and ground, and cesisEor 102 is coupled between the inverting input of operatjonai amplifler 98 and the output of operationsi amplifier 98. In iNs configuration, operationai amplifier 98 is operated as a single pole, low pass filter. The cut-off frequency of this iow pass filter is established by the values of resistor 94 and capacitor 96. Preferably, the cut-off frequency for this low pass filter is 2 Hertz 9 5 The output of operational amplifier 98 Is provided, through capacitor 104, to the non-invertjng input of operational amplifier 106. Resistor 108 is coupled between the non-inverting Input of operatjonal amplifier 106 and ground, while resistor 110 is coupled ba$ween the inverting input of operational amplifier 106 and ground. In this configuration, operational amplifier 106 is performing the operaiions of a high-pass fiit,er. The cut-off frequency for this high pass fifher is prefierably I Hertz, and is established by the values selected for capacitdr 104 and resistor 108.

The output of operational ampiifier 106 is supplied through capacitor 112 to the non-inverting input of operatjonal ampiifier 114. Capacitor 112 AC-couples operational amptif'ier 106 to operational amplifier 114.
Therefore, no DC component is passed to opera6onai amplifier 114. The inverCing input of operational ampi'd=ier 114 Is coupled to the voftge divider established by resistors 116, 118. In this coni=iguration, operational amplifier 114 is operating as a positjvs voltege ievel debecbor. As such, the output of operational amplifier 114 remains low untii a voltage is supplied to the non-inverting input of operafionai amplifier 114 which exceeds the posit3ve voitage (Võf) which is applied to the inverting input of operational SUBSTITUTE SHEET (RULE 26) wo 96124752 PGTIU596101612 ampiifier 114. Once the volis;ge at the non-inverting input exceeds thes voltage applied to the inverting input, the output of operational amplif'ier switches from iow to high. Preferably, the output of operational ampiifier 114 is appQed through terminel 120 to a memory device, such as a flipaltop (not depicted), but it may be applied dir-ectiy to an input twminal of a pulse counting circuit which will be described in greatter detail below.

7. THE STRAIN GAGE TYPE SENSOR: . The s#rain gage technique, which ts an alternatlve to the pressure transducer technique, is depicted in simpfified form in Figure 6. The strain gage technique requires the utilization of one or rnors strsin gage sensors to detect circumferential etastic deformation of centtal bore 95 of tubular member 19. Figure 6 depicts the placement of tangential strain sensor elements 291, 293. As shown, tangentiai strain sensor elemerft 291, 293 are praced substantiaNy traverse to the longitudinal axis 299 of mandrel member 59.
The magnitude of the tangential strain detected by strain sensor elements 291, 293 is of little importance; the proposed product utiibes a system which monitors only the rate of change in pressure amplitude as compared to a preesure ampiitude thnsshdd to detect ac:oustic pulses.
Accordingly, the plaoenient of #angential strain sensor elements 291, 293 relative to tubular member 191s of little Importance. As is shown in Figure 6, tangential strain sensor element 293 may be displaced from tangential strain sensor element 291 by fifteen to thirty degrees. In alternative embodiments, the sensors could be displaced one hundred and etghty degrees. Their physical proodmity to one another Is of lfte importance.
Only their ability to detect circumferentiai eiastic deformation matters. The tangential strain sensor eiemnts 291, 293 need not be cafibrafied or temperature compensated, since the reception apparatus monita s only for rapid rates of change in fluid pressure ampiitude, and is not the least concerned with the magnitudes of fluid pressure wftNn the fluid cohxnn.
Figure 7 is an elecbical schematic view of an electricai circuit, which incdudes tangential bridge circtdt 307. TangenUal bridge circuit 307 SUBSTTfUTE SHEET (RULE 26) w0 96124TS2 pCTlIiS96101612 includes four elements, two of which are used to detect stress, and two of which are used to complete the bridge oir+cuit. Tangentiai bridge circuit 307 lncludes tangential strain sensor element 291 and tangentiat sirain sensor element 293. In tangentiai half-bridge 307, tengentiai strain sensar 291 and tangenUal strain sarisor 293 are pieced opposite from one another In a"half-bridge" arrangement. Bridge completion resistors 315, 317 are placed in the remaining two legs of a fiAl bridge circuit.

In Figure 7, tangential atrain sensors 291, 293 ara represented as electrical resistive components. In the preferred embodiment, tangentsal strain sensor elecnents comprise Bonded FoR Strain Gages, manufactured by Micro Measurements, of Raleigh, North Carolina, further identified as Model No. SK-06-250BF-10c, with each element providing 1,000 ohms of elactricai resistance to current flow. Likewise, bridge comple#ion elements 315, 317 are depicted as electrical resietive elemerrfs. As shown, tangential strain sensor element 291 is coupled between nodes I and 3 of tangential bridge c.ircuit 307. Tangentiai strain sensor 293 Is coupled between nodes 2 and 4 oF tangential bridge circuit 307. Bridge compiWon resistor 315 is coupled beiween nodes 2 and 3 of tangentrat bridge circuit 307. Bridge completion resist,or 317 is coupled between nodes I and 4 of tangential bridge circuit 307. Positive 2.5 votts is applied to node 1 of tangential bridge circuit 307. Negative 2.5 vdts is applied to node 2 of tengential bridge circult 307.

Bridge completion resisfiors 315, 317 are not coupled to a conduit member 209. In fact, bridge cornpletion elements 315, 317 do not sense any mechanical strain whataoever. Instead, they are placed on carrier member 319 (not depicted) which is disposed within sensor caviiy 67, and not subjected to any mechanical stress. They merely compiete the bridge circuit The "active" tangential strain sensor elements 291, 298 will change electrical resistance in response to mechanical strain. Tangential strain ~ ~~~ ~~AN) WO 9612A752 PCT/[TS96/01612 sensor elements 291. 293, are bonded to the exterior surface of mandrele member 59, and experience stain when condutt member 209 is subjecbed to tangential stresas. The voltage applied to nodes I and 4 cause current to flow in tangential bridge crcuit 307. The r+esulting voltage developed between nodes 3 and 4 of tangential bridge circuit 307 is represented in Figure 7 by Vt, which idenHiSes the voltage representathre of the tangential sb ain detected by tangential bridge cirp* , ift307.

The voftage Vt which Is representative of the tangential strain detected by tangential bridge circuit 307 is then subjected to signal conditioning operations which are depicted in block d'iagram form in Figure 7. In accordance witlh signal condit3oning block 122, the voltage Vt is subjected to DC atnplification, preferably of one hundred gain. Capacitor 124 is utilized to AC coupie signal oonditioning block 122 with signal 9 5 candifiionin8 block 126. In signal conditiordng block 126, the AC
component is subjected to AC ampliiication of one hundred gain. The signal is then passed to signal concRtioning block 128, which performs a bandpass operation to allow for the passage of signals in the range of one to two Hertz, but which blocks all other frequency components of the signal. The signal r.omponent In the range of one to two Hertz is then passed to signai processing block 130 which perfoanns a comparison operation, preferably to identify rapid rates of change in the pressure amplitude which are greater than two hundred and fiRy pounds per square inch per second.

The voltage amptitudes of various rate changes can be detsrmined empirically through experimentation, by u6lbft a test fixture to simulate a borehole and stepping through a plurality of known fluid pressure rate changes to determine corresponding voltage ieval of V.w for comparator 130. Essentially, signal processing block 130 operates to compare the voitage amplitude which is provided as an output from signal conditioning block 128 to a sek3cted voltage threshold estebiiehed by Vr O, which is representative of a rate of change which is equivaEent to two hundred and fifty pounds per square inch per second. Ampptudes which exceed the SU65TITUTE SHEET (RULE 26) w0 96J247s2 PCTI[JS96/01612 r+eference voitage are determined to exceed the rate of change or two hundred and fifty pounds per square inch per second, and operate to swotch the output of the comparator from a normally-low condition to a high cond'iljon. The output of signal processing block 130 Is provided to signal condidoning biock 132, which.is preferably a flip-flop, which includes one or nsore output pins which change state as a result of detection cf a transition at the output of signal conditjoning block 130. The particular components of the signal conditioning operations will be discussed in greater detaii herebelow in connection with Figures 8A and 88.
8. THE PRESSURE CHAN DETECTION CIRCUIT: Figures 8A and 8B sre an electrical schematic depiction of pnossure change detection circuit coupled to tangential bridge circuit 307, which was discussed in considerabie detail above in connectjon with Figure 7. As is shown in 15 Figures 8A and 88, V:, the voftage which is representntive of the tangential strain, is applied between the inverting and non-inverting inputs of operational amplifier 319, which is operated as a diffferenlial DC ampiifeer, with a gain of approximateiy 100, as deterrnined by the selection of the resistance values for resistor 313, and resistor 315. The output of 20 operational amplif'ier 319 is supplied through capacitor 321 to the non-inverting input of operational ampfcPier 327. Capacitor 321 and resisW 320 provide AC coupiing between operationat ampiifier 319 and 327, to aliow only the alternating current components of the output of operationai amplifier 319 to pass to operational amplifier 327. Operationai amplifier 25 327 operates as an AC ampiWor to provide a gain of approximafiely 100, as determined by selection of the resistance values for resisbxs 323, 325. The output of operational ampi'fier 327 is supplied through a bandpass fitter established by capacitor 329, resistor 331, resistor 335, and capacitor 333, to the non-inverting input of operationai ampiifier 341. The band-pass filfer 30 established by the capscibve and resistive components aiivws the passage of frequencies of 1 to 2 Hertz only, and blocka all other frequency components of the output of operational amplituer 327.

SUBSTiTUTE SHEET (RULE 26) W o 9fiJ24732 PCTliJS96l01612 9. FREQUENCY DETERMINATION CIRCUIT:, Figure 9 is. a block diagrame representation of the digital circuitry which procomm the pulses detected by puise detection circuit 401 (which corresponds to the pressure change detection circuit of Figures $Akan'i:l 88. The detected puises are passed from circuit pulse detection circuit 401 to puise counter 403. Those pulses are counted if, and oniy If, an enable signal Is provided on the ENABLE
COUNTER line. The ENABLE COUNTER line applies an enable signal to pulse counter 403 at a predeter'mined frequency. The ENABLE COUNTER
line provides the enable signa! for only six seconds. This renders the pulse counter 403 inactive for most of the operating time, and active for onty six seconds at a predetermined frequency.

In the proposed product, the predetarrnined frequencies which may be utilized to actuate a partlcular downhole tool are muitipim of thirty second intervals, as defined by thirty second timer 407. In other words, the actxration frequencies that are availabie for use are nmttipies of thirty aeconds. An actuatiwt frequency which utiliss a multiple of I will result In enablement of pulse counter 403 for six seconds every thirty seconds, resulting in an actuation frequency of 1130 of one Hertz If, and only if, an acoustic transmission is detected which has this same frequency wdl a welibore tool be actirated. An actuation frequency which utilixes a multipie of 2 will result in enablement of pulse cotater 403 for six aeconds every sixty seconds, resuiting in an ackiation frequency of 1160 of one Hertz. !f, and only if, an acoustic trenamission is detected by pulse detection circuit 401 and pulse counter 403 which has this particular frequency wiil a welibore tool be actuated. An actuation frequency which utli"u3es a mctttipie ol' 3 will result in enablement of pulse counter 403 for six seconds every ninety seconds, resulting In an acduation frequency of 1190 of ane Herti. If, and only if, an acoustic transmission is detected by pulse detection circuit 401 and pulse aunter 403 which has this particuiar frequency will a welibore tool be actuat,ed.

SUBSTiTUTE SHEET (RULE 26) w0 96I24752 r , ,~ PCTI[JS96lo1612 1G-1 Q'~ 0.1 ~

~ Thirty second timer 407 provides its output to frequency counter A
409. frequency counter B 411, and watch dog timer 413. Frequency counter A 409 and frequency coanber B 411 are utJiized to allow each particuiar welibore tooi to be rernoteiy achuaitied utilizing two ditferent acouslic pulse frequencies. The binary value of frequency counter A 409 establishes the particuiar muilipie of thirty seconds which defines a first actuatJon frequency (1/30 of 1 Hertz; 1160 of I Hertzz 1190 of I Hertz, et,c_).
The binary value loaded into frequency counter B 411 Is utilized to establish the multiple of thirty seconds which defines a second frequency of acous6c pulse transmission (1130 of I Hertz; 1180 of 1 Hertz; 1190 of I Hertz, etc.).
Preferably, pulse counter 403 may be jumper-con6gured to allow it to be either responsive to a single acoustic ttansmiasion frequency or to two consecutive acoustic transmissiai frequencies. The values of frequency counter A 409 and frequency counter B 411 are deten,nined by an eight bit number which is loaded by microprocessor 417 Into shiFt register 415. The four least significant bits of shiR, register 415 are loaded to frequency counter A 409, while the four most significant bits ar shift register 415 are loaded into frequency counter B 411. Microprocessor 417 3nteracts only with shift register 415, and only for the purpose ofi loading the binary values to shift register 415, which are then bansferred to frequency counter A 409 and frequency counter B 411.

Frequency counter A 409 receives as an input the thirty second timer pulse from thirty second timer 407, and produces as an output an enabie signal which is simuttaneousty applied to ENABLE COUNTER line and ENABLE TIMER line. Frequency counter A 409 produces an enable signal at a multiple of the thirty second interval which is defined by the binary value of the four bit nibble loaded from shift regisbeir 415 to frequency counter A 409. Frequency counter A 409 only provides the enable signal for the first four pulses; thereafter, frequency counter 8 411 provides an enable signal to ENABLE COUN'TER line and ENABLE 71MER line at a multiple of the thirty second interval, depending upon the binary value of the four bit nibble loaded from shift registe~ 415 to frequency counter B 411.

SU6STiT'UTE SHEET (RULE 26) WO 96124752 PGTNS9blU1612 Thus, frequency quency counter B 411 controls the monitoring of the next four*
possible puises. in tlWs mamer, #he first four detecWd acoustic pulses may define a first particular frequency, while the next four detected acoustic pulses may define a second, d'dferent, ac:oustic tranansission frequency. In this manner, two-hundred fitty-six poossibie=,.aciuafion signals may be provided. This allows for the ub'fixation oF'a wide variety of romotely-acdusted wellbore tools in a single atrfng. For bath the first four and iast four actuation pulses, watch dog timer 413 operates to aut+omaticafiy reset the entire frequency moniboring system should an actuation pulse faif to be detected during the six second window of sirnultaneous enablement of pulse counter 403 and watch dog timer 413.

In the preferred erabodiment of the present invention, the frequency detsrmination circuit further includes a reset register 408 which receives a signal from pulse counter 403 when a pufse has been detected. Reset register 406 responds to the detection of a puise by puise counter 403 by applying a timed disable signal to pulscr counter 403. This renders pulse counter 403 Insensitive to echos of the acoustic puise just detected. Bear In mind that the fluid column in the wellbore is generally a relatively closed fluid body, and that an acaastic pufse may reverberats or echo in the fluid column for a brief Interval atter tranemiasion, as It bounces off of the weilbore bottom and the welihead. Additionaiiy, the acouistic pulse may reflect or echo off of weifbore tools or wellbore structures which are intermediate the wellhead and wellbor+e bott,om, so a plurality of different reflective swfaces exist which may aet up a series of r+everberations of the acoustic transmission which generalfy subside or diminish in amplitude relaEiveiy quickly. Application of a timed disable signaf to pulse counter 403 ensures that the echos or reverberations of the acoustic transmission are not erroneously detected by pulse counter 403. Preferabty, the duration of the time disable signal Is in the range of ten to fifteen seconds. This timed disable interval may be aet for shorter or longer periods depending upon empiricat evidence developed through prolonged use of the apparatus oF
the present invention.

SUBSTITUTE SHEET (RULE 26) w() 96124757 PCT/IT896/01612 ~
Figure 10 harQbebw depicts a two frequency actuation transmission. The firat four acoustic pulses are separated by thirty seconds (which nreans that the binary vaiue of 0001 has been loaded Into irequency counter A 409). This resuits in a firat actuation frequency of 1130 of one Hertz. The next faur acoust3c putses are separated by sixty seconds (which means that the binary value of 0010 has been loaded Into frequenay counter B 411). This resuits In a second acbmbon frequency of 1160 aF one HerbL if microprocesscr 417 has baded the binary word "00100001" into ah1#t register 415, then the four least signiiicant bits (0001) have been loaded into frequency counter A 409 and the four most significant bits (0010) have been loaded into frequency counter 8 411, making the particular welibore tooi responsive to the consecutive acoustic transmission frequencies of 1l30 heriz (for the first four pulses) and 1160 Hertz (for the next four pulses).
The apperation of the communicatiion system aF the present invention is depicted in simplified form in the block diagram view of Figure 11. As is shown, transmission apparatus 51 is rernotely located from reception apparatus 53. Transmission apparatus 51 is utilized to generate a comnmand signal 52 in a communication channel 50. Pneferabty, the conanand signa! 52 is composed of acoesgUc puises which define one or more acoustic transmission frequencies. In the embodiment depicted in Figure 11, connmand signal 52 indudes a first frequency cornponent 54 which defines a reiativeiy high frequency signai, and a second frequency component 56 which defines a relatively low frequency transmission.
Sensors 58 within receiver 53 are utilized to deteat the acoustic pulses, and transmit electrical signais representative thereof to logic circuit 60. Logic circaiit 60 provides an actuation signal to fire circuit 62, if and only if, the one or more acoustic tranamission frequencies correspond to one or more predetermined acousfic transmission frequencies which are programmed into logic circuit 60. Once a match Is obtained between the detecW
acoustic transmissions and the predeternnined frequencies, an actaai;ion signal Is provided to fire circuit 62. Preferably, fire circuit 62 comprises a SUBSTRUTE SHEET (RULE 26) wo 96/24752 2187010 PCT1US96101612 switching circuit which impedes the flow of current 66 from voltage source 0 V+ to ground, until an acbration signal Is provided by logic circuit 60. Fire circuit, when activated, allows current.. 66 yto pass to end device 64.
Preferably, end device 64 Is an eleplr3eally-aduatsd wellbore tod.
10. THE PROGRAMMING TERMINAL _ Figure 12 is a picboriai representation of a progrwnming torminal 91 which is utitized to allow bi-directional communication with nWc%processor 417 before roeception apparabis 53 is run hnto position within a weilbore, and is especially usefui in programming a particular reception apparatus to be responsive to either one or two particular acoustic transmission frequencies.
In the preferred embodiment of the present invention, programming terminal 91 may be utilized In either (1) ai transrnitting mode of operation or (2) a receiving mode of operation. In ttie transmitting rnode of operation, progranuning terminal 91 is utilized to produce a plura5ty of dOfferent ASCiI
characters. As is shown in Figure 12, a pluraiity of dedicated keys are provided with human-readable aiphanurrieric characters disposed thereon.
The depression of a particular key by the human operator will nHSult in the generation of a particular, predetermined ASCII character which is directed through electrical cord 125 and electriicaliy connector 127 to reception apparatus 53. In a receiving mode of operation, programming terminat 91 is utAized to receive ASCI! aharacters from receiver apparatus 53 through electrical cord 125. Programming terminal 91 includes a fiquid crystai display (LCD) 129 which is utilizeid to present human readable alphanumeric text which contains useful information from reception apparatus 53. In the preferred embodiment of the present invention, programming terminal 91 is eiectricaliy connected to receiver apparatus 53 only during programming and testing operations. Programming terminal 93 is disconnected from recepfton apparatus 53 after It has been adequately programmed and tested. 7hereafter, reception apparetas 53 is run into a desired location within a wellbore, and requires no further interaction with programming terminal 91 to perForm its program functriona.

SUBSTiTtTCE SHEET (RUI.E 26) WO 96124752 PGT1U'896/0I612 As can be seen from Figure 12, programming terminal 91 Includes a plurafity of aiphanumeric keys, including: an "ON" key and an "OFF key which are utilized to turn prognamming terminal 91 on and olF, an initiatize key which carries the letter "1" which is utilized to enter a programming mode of operation during which reception apparatus 53 is prograrnmed to respond to one or two particcdar acoustic pulse ttansmlaeion frequencies; a fiest key which carries the character'T" which is utilized to test a variety of electrical characteristics of reception apparatus 53, as wii! be described herebelow in further detail; a read key which carries the character "R", and which is uEilized to read data from reception apparatus 53 to allow confirmation of the programmed content of reception apparatus 53. Keys with the numeric characters 0 thropgh 9 are also provided in programming terminal 91, as well as a"YES" key, a "NO" key, and an enter key which carries the character "E", all of which are utiiized to respond to microprocessor generated queries displayed at 1.CD display 129.

In the preferred embodiment cf the present invention, exchanges oP
information between the human operator and recatption apparatiss 53 are faciiitated by a plurafity of automatically generated prompts and operator queries. The "YES" key and the "NO" key can be utjlized to contirm or deny the accuracy of a human operator enby at programming tenninal 91. For example, if an operator socidentally enters an umorreot value during the programming mode o# operadon, the user prompt provides an opportunity to correct the error before receiver apparatus 53 Is progrananed.
Figures 13A, 13B, and 13C provide graphic representatian examples of the utiiitation of programming tsrminal 91 to program reception apparatUS 53, to test pardcular functions of reception apparab 1s 53, and to read particular data from programining apparatus 53.
Figure 13A depicts the alphanumeric characters dispiayed in LCD
display 129 dw'ing a programming mode of operation. Once the inttialize key is depressed, LCD display 129 displays the message "initialize system"

SUBSTtTUTE SHEET (RULE 26) W096/24752 PCT1U8961p1612 as depicted in blook 131. The tnicr+oprocessor within programming terminate 91 then provides the user prompt whic==h is depicted In block 133 which prompts the user to enter the first acousitic tanamission frequency which is identifeed as "FREQ NO. V. In aocordance with block 135, the user then enters a number from the keypad of prognanuning unit 91, and the LCD
dispiay 129 provides an opportunity for the eiser to delete an incorrect entry and provide a correct entry by prompting "OK (YIN)", which prompts the user to depress elther tlm "YES" key or ihe "NO" key. Then, in accordance with block 137, programming terminal 91 prompts the user to enter the second acoustic tranamission frequency which is identified as "FRFQ NO.
2". The operator should respond by pressing particutar ones of the numeric keys in programming terminal 91. in accordance with block 139, programming terminal 91 informs the user of his or her selection and prompts the user to depress the "YES" key or the "NO" key to confirm the accuracy of the entry.

In another ermbodirnent, r+eceptjon apparatn 53 can be preprogrammed with a pluratity of predefined codes sach of which is assigned a predetermined idontifying numeral, to simplify the programming process. For example, the following identHying numerala can be assigned as follows:

Identifying Nunrerai Transmission Frequency 1 1130 Hertz 2 1/60Hertz 3 1180 Heriz 4 1K20 Hertz 5 IH50 Heriz 6 11180 Hertz Figure 13B is a representation of a tsat operation. Alphanumeric display 129 displays the prompt "'FFMT" In response to the operator SUBSTITUTE SHEET (RUL.F 26) wo 96/24752 PGT/[7S96l01612 selection of the test key. In accordance with block 143, the operator Is prornpt,ed to select a particular function for which the test is desired. The firnction keys Fl, F2, F3, and F4 are prede!'ined to comespond to a particular functions. In accordance with block 145, the operator aeiects a particularfunction. The microprocessor reads the data from reception unit 53 and displays it, in accordance with block 147.

In the preferred embodiment of tfie present invention, programming terminal 91 will provide the following disgnostic capabilities:
i. it will display the appraximat~e battsry Gfe remaining on command from the user;
2. it will disptay the InitiaEit$tion variables an command from the user;
3. it will conduct an EEPFtOM Test on command from the user, 4. It will conduct a dmer test cn command from the user, S. iEwill enable any igni6er circuits on commmnd from the user;
6. it wiN conduct a battery kmd fiest to verify that the baiteries are capable or supplying the necessary current to ignite the actuation system;
7. it will determine if any of the i8niters in the actuation system are open;
8. it will display a ROM Check Sum on command from the csser;
and 9. it will display an EEPIEtOM Check Sum on command from the user.

Figure 13C is a repmenbstion of a read operation, which is initiated by depressing the read key. LCD disptay 129 dispiays a prompt to the user that the read mcde of operation has been entered, as depicted in block 149.
Next, in accordance with block 151, the user Is prompted to select a particular function. Once again, the functions keys Fl, F2, F3, and F4 are preassigned to particular data which may be accessed through a read SUBSTITUTE SHIEET (RULE 26) WO 9W?4752 PCT1US96/U1612 operation. The operator enters a particular function, as depicted in bloc*
153. Then, in accordance with block 155, the LCD display provides an alphanumeric representation of the particutar data reqaosted by the operator. In the case shown In Figure 130, the LCD display 129 displays the first and second acausfic transmissian frequencies uniquely asaoc~ated with a par6cufar reception apparatus. This is depicbed in block 155.

In the preferred embodiment ofthe present invention, programrning terminal 91 is a hand-held bar code tmnanal which is manufactured by Computerwise of Olathe, itansss, and vvhich is further identified by Model No. TTT-00. It may be programmed for particular fiuyctions In accordance with instructions provided by the manufacturer. In the present imrention, it ia customiz,ed by the addition of an interFace circuit which wiQ be described in detail in Figures 14,15, and 16.

11. QYgRyIEff OF THE RECEPTION APPARATUS: Figure 14 is a block diagram view of reception apparatus 53, actuator 27, and wellbore tool 29, disposed within housing 95, and releasably electrically coupled to programming terrninal 91. As is shown, programming termina! 91 includes interface circuit 101 which is electrically connected by eiectricat connectors 97, 99 to connector 93 whiich Is carried by housing 95. As is shown, connector 93 allows for the electrical connection between interface circuit 101 and eiectromsgnetic coil 103. Elsctrornagnetic coil 103 is separated from chamber 107 by barrier 109 which includes seai 111 which serves to prevent the leakage of fluid into chamber 107 which includes delicate electronic instruments which nzay be easily damaged by moisture.
Electromagnetic coii 113 is disposed within chamber 107. Electromagnetic coils 103, 113 are utilized to transmut ini'ormation across barrier 109, allowing an operator to program central proce sing unit 117 to respond to parkicLtiar coded messagea through the utilization of programming terminal 91, and to allow pragramwning tertninal 91 to be uEilized to receive information from central pracessing uinit 117. As is shown In Figure 14, interFace circuit 115 is provided between eieatrosnagnetic coil 113 and SUBSTITUTE SHEET (RULE 26) WO 96/24752 PGT/US%/01612 21S?010 central processing unit 117. Senaor(s) 119 provide data to central proceasing unit 117. Centrai processing unit 117 continuously analyzes data provided by sensor(s) 119, and providea an aclyuation signal to actLator 27 upon recogrdtlon of a coded message which It Is programmed to respond to during a programming mode of operation. Actuabor 27 in turn acfiuates wellbore tool 29 to perform a weilbore operation. WeRbom tool 29 may be a packer, perforating . gun, valve, liner hanger, or any other conventionai weilbore tool which may be utilized to aocorroish an engineering objective during Wlling, completion, and production operations.

Figure 15 is a simpiified and partial longitudinal section view of welibore communication apparatus 11, and depicts the interaction of electromagnetic coil 103 and eiectranagnstic coil 113. As is shown, mandrel mernber 59 includes recessed region 50 which is adapted to receive the windings of electromagnetic coil 103. In this figure, conneeWr 93 is depicted in simplified fonm; it allows the releasable electrical connection with programrning tenminal 91. Mandrel member 59 further includes recessed region 52 which is adapted for receiving the windings of electromagnetic coM 113. SeaE 111 is disposed in a poeition intermediate electrornagnetic coil 103 and eleatroniiagnetic coif 113, and is carried by barrier 109 which at least partiaily defines a housing which surrounds chamber 107. As is shown, electromagnetic coil 113 is disposed within the sealed chamber 107, while electramagnetic coii 103 is disposed ext,erioriy of the sealed chamber 107. In lfiis carfguration, mandrel member 59 operates as the core of a tranefag sner. Electrical current which passes through electromagnetjc coil 103 generates a magnstic fieid wWdn the ferromagnetic material of mandret member 59 (mandrel member 59 is typica3liy formed of oil-field grade steel). This magnetic field passes through mandrel member 59 and induces ia current to flow within the windings of electromagnetio coil 113. In this nianner, the windings of electromagnetic coils 103, 113 and mendrel member 59 together form a magne#ic circuit component which Incorporates the sbvc6ural ferTomagnetic component 59 SUBSTITUTE SHEET(RULE 26) WO 96!24752 2187010 PCT/U596101612 in a manner which facilitates communication acroes seal 111 and barrier=
109 without having direct eiectrical connection therebetween. These componenls together cooperate as it "transfonmer" with a gain of approximately one. Whert porrimunicntion is desired in the apposite direction, electricai currwt is passed through the windings of eiectromagnetic coil 113. This causes a megnetic flux to flow through the ferromagnetjc materIal of mandrel member 69. The magnetic flux passing through mandrel member 59 causes a current to be generated In the windings of electromagnetic coil 103. 'The electrical current is directed outward through connector 93 to programming terminal 91.

12. THE MAGNETIC INTERFACE TERMINAL OF THE PROGRAMMING UNIT:
Figure 16 is an eiecbical schematic depictfon of interface circuit 101 of programming terminal 91, which is coupled to terminal microprooessor 100 at DATA-IN pin and DATA-OUT pin. The passage of current through electromagnetic coil 113 (of Figure 14) generates an electromagnetic field which causes the deveiopment of a vdltage across electromagnetic coil 103. Snubber capacitor 211 allows electrcmagnetic coil 103 to change its voltage level rnore rapidly, but also rmnft the vdtage across electromagnetic coil 103. As shown, a vrltage of slightly leas than five volts is applied to the non-inverting input of operatjonal amplifier. The inverted valtage which is developed across eisctromagnatjc coil 103 Is also provided to the non-inverting input of operatianal ampiifier 219.
Operational amplifier 219 is configured to operate as a positive voltage level detector. As such, the output of ioperational amplifier 219 remains high, for so long as the voitage provided at the nonWnverting input of operattonal amplifier 219 exceeds the amall vdtage Vg which Is supplied to the inverting input of operational ampiifier 219. The neftrence voltage Vre which is applied to the inverting inpult of openationa! amplifier 219 is established by selection of the resistance values for resistor 217, resistor 213, and resistor 215. As is shown in Figure 16, five votts is applied to one terminal of resistor 217; this five volte c:auses a small cutrent to flow through resistors 217, 213, and 215, estsiblishing the reference voltage Võt SUBSTiTUTE SHEET (RULE 26) WO 96l24752 2 187n 10 PGTlUS96/01612 at the inver6ng input of opeeational amplit"ier 219. When the sum of voltages applied to the non-inveriing input of operational amplifier 219 falls below the voltage level of the voltage applied to the inverting input of operagonal amplifier 219, the output of operationai amplifier 219 goes from high to low, and is detected by terniinaf ' 100 at the DATA-IN
pin.

The DATA-OUT pin of terminal microprocessor 100 may be ub'iized to selectlvely energize electromagnetic coii 103 to communicate a binary stream of ASCII characters to electromagnetic coil 113 (of Figure 14) and interface circuit 115 (of Figure 14)õ As is shown in Figure 16, the output of the DATA-OUT pin of lverminal microprocessor 100 is applied through inverter 229 to field eifect transistor 231. The output of the DATA-OUT pin of terminal microprocessor 100 is also applied through inver#ers 227, 225 to field effect transist,or 223. Field effect transistor 223 is a P-channel field effect transistor, but field effiect bainsistor 231 is an N-channel field effect tranaistor. When the DATA-OUT pin of terminal microprocessor 100 goes high, field effect transisfiors 223, 231 switch on, allowing the five volts OC
(which are applied to one input oF field effect tremsistor 223) to be applied across electromagnetic coil 103, to cause an electromagnetic fielld to be generatad which Is detected by electr+omagnetic ca"I 113 (of Figure 14). A
stream of binary ASCII characters may be provided as a serial output of terminai microprocessor 100 at the DATA-OUT pin. The binary characters cause the selective application of vottage to electromagnetic coil 103, which is detected by electromagnetic coil 113. Interface circuit 115 (of Figure 14) is utilized to reconatruct the serial binary character string which Is representative of ASCII charactens.

13. THE MICROPROCESSOR CIRCUIT: Figure 17 Is a block diagram depiction of the electrical components which cooperate together to perform the operations of reception apparatus 53. Figures ISA through 20 provide de#su'led electrical sdternatic views of various components of the biock diagram view of Figure 17.

SUBSTtTUTE SHlEET (RULE 26) WO 96124752 PCf/IIS96/01612 As is shown in Figure 17, microprocessor 255 interfaces with a pluw aiiiy of eleaite icai components. Clock 239 provides a clock signal fior microproceseor 255. EEPROM 259 proWdes an electrically-erasable memory space which is utllized to record infamation provided by the operator during the programming mode of operation. PROM 257 is utllized to store a computer pro8ram wh'-ch is executed by microprocessor 255.
Microprocessor 255 receives and transmits information through magnetic communication interface circ:uit 115 during initia[ization of the system, testing of system components, or reading operations, all of which are performed through utiifzation of programming terminal 91. Magnetic communication interface 115 communicates with microprocessor 255 through DATA-OUT pin and DATA-IN pin to transmit serial binary data streams which are represenfative of ASCII characters.

Microproaessor 255 comrnunicates in a limited manner with the circuit components of reception apparatus 53. First, it provides a "BLOW
command to pawer-up circuit 234 (the details of which will be provided beEaw). Second, it provides a binary eight4it word to Wgic circuit 80 as was discussed in detail above.

Just before the reception apparatus is kywered inibo a we!lborv, the operator utiiizes terminal 91 to communicatie with microprocessor 256 through magnetic communicatjon intert'aae circuit 115. This commences the initiation of the tool. The first magnetic pulse triggers the operatian of microprocessor power-up circuit 254. Microprocessor 255 utilizes a program stored in PROM 257, as well as binmy vaiue stored In memory of EEPROM 259. Microprocessor 255 directs a digital carnrnand through "BLOW" iine to power-up circuit 234. This causes the application of power to pressure change detection circuit 401. Then, microprocessor 255 utilizes the LOAD SHIFT REGISTER line to pass an eight-bit binary word to logic circuit 60.

SUBSTITUTE SHEET(RULE 26) WO 96/24752 PGT![TS96P01612 =
The receplion apparatsas 53 Is then lowered into the weiibore.
Sensors 58 detect the transmission of acoustic pulses thn%gh a fluid column in contact with receptlon apparatus 53. The raw sensor data is directed from sensors 58 tc pressure change detection circuit 401, and are supplied to logic circuit 60 which is utilized to detertnine whether the acousf5ic transmissions match the one or more transmission frequencies which this particular raeception apparatus is programmed to be responsive to. tf a match is found beiween the transmission frequency of acoustic pulses and the preprogrammed one or two acoustic transmission frequencies, then logic circuit 60 supplies a command signal to fire circuit 62. Preferably, fire circuit 62 is siniply a transist,or switching circuit which aqows the applicatjon of a relatively high amount of current to end device 64.
The folfowing secbons discuss the operaEfons of magneflc communical;ion interface circuit 115, power{ep circuit 234, and microprooessor power-up circuit 264.

14. THE MAGNETIC COMMUNICATION INTERFACE OF THE RECEPTION
APPARATUS: Figures 18A and 1813 are an electrical schematic depiction of magnetic communication interface circuit 115, which receives signals from electnomagnetic coil 103, which Is part of programming tetminal 91.
The voltage which is developed acnxs elecMornagnetic coif 113 is applied to operationaf ampfifier 289, which is operated as a positive voltage level comparator. Positive five voits DC Is applied tluough resistor 280 to the non-inverting input of operational amplifier 289. The inverse of the voltage which is developed across eiectromiagnetic coil 113 is aiso applied to the non-Inverting input of cpera#ionaf amplifier 289. A small DC current flows through resistor 280, electrcmagnelbc coil 113, resistor 286, and resistor 287, to ground. The voltage developed across resistor 287 is applied to the inverting input of operational amplifier 289. When a digital signal is received, the voltage developed acrces electromagnetic coil 113 is SUBS?7TUTE SHIEET(RULE Z6) subtracted from the slightJy less than five volts applied to the non-invertinge input of operational amplifier 289, causing the voltege detected at this input to decrease and eventually fall below the voltage level applied to the inverting input of operational amplifier 289. As a consequence, the normally-high output of operational aniplifier 289 switches low for the duration of the binary signal raeceived Ey electromagnetic coil 113. This voltage is applied through resistor 305 to the DATA-IN terminal of microprocessor 255. Additionally, the voltage is passed through the low-pass fiiter established by resistor 282 and capacitor 307 to the CLOCK
input of flip-flop 309, causing the Q output of flip-flop 309 to go from a normally-low state to a high state. As is shown in Figures i8A and 188, the Q output of flip-flop 309 is supplied to the ONU terminal of microprocessor 255. As will be discussed in greater detatl herebelow, the CLEAR output of microprocessor 255 may be utiilzed to reset flip4lop 309 and cause the output of the Q pin to go irom high to low.

The magnetic communication interface circuit 115 also allows microprocessor 255 to transmit a seria0 strearn of binary bits, which are representative of ASCII characters, through electromagnetic coil 113. The binary character string is applied to the inagnetic communication interface circult 115 through the DATA-OUT pin of microprocessor 255. A binary zero which is applied to the DATA-OUT pin of microprocessor 255 causes a binary zero to be applied to the gate of N-chennei field effect transistor 275, and a binary one to be applied to the gate of P-channel field effect transistor 277, allowing current to flow from BATTERY I through fieid efFect transistor 275, inductor 113, field effect transistor 277 to ground. The passage of current through electromagnetic coil 1131 creates an electromagnetjc field which may be detected by eleatromagnetic coil 103. The application of a binary one to the DATA-OUT pin of miicroprocessor 255 prevents the passage of current through field effect transistors 275, 277, thus preventing the passage of current through electromagnetic coil 113 and preventing the generation of an eleatrornagnetic field. In this manner, a binary zero is represented by the creation of an eiectromagnetic field at SUBSTITUTE SHEET (RULE 26) wo 9612A752 PGT/US96JD1612 electromagnetic coil 113, while a binary one is represented by the absence of an electromagnetic field at aleciromagnetic coil 113. The sequential presence or absence of the alectnomagrmtic fields at elactromagnatic coil 113 represents a serial binary data stream, which may be detected by electromagnetic coil 103 and which may be reconatrucbed by interface circuit 101 and directed to the terminal nuoroprocessor 100.
15. THE POWER-UP CIRCUIT FOR PRESSURE CHANraE DE'PECTION
CIRCUIT: Figure 19 is an electnicai scherrwtic depiction ofipower-up circuit 234, which Is utiiimd to allow microprocessor 255 to allow the consuntptlon of power by the pressure change detection circuit of Figure 8, only after reception apparatus 53 has been initiaiized by the operator.
Microprocessor 255 utiiims the BLOW output pin to blow fuse 369 which the causes the application of power to the components which comprise the pressure change detectjon circuit. As is shown in Figure 19, the BLOW
output pin of microprocessor. 255 is coupled to the gate of field effect transistor 375. The drain ci field effect transistor 375 is connected to BAITERY 2 through fuse 389. Application of voltage to the gate of field effect transistar 379 allaws current to flow from BATTERY 2 through fuse 369 and field efFecct b ansiator 375 to ground, causing fuse 389 to blow.
Prior to blowing of fuse 369, the valfte of BATTERY 2 is directly applied to the gate of field efirect transistor 371, causing the transistor to be turned a(f.
Resistor 373 shoWd be sufficiantly large to lirnit the current flowing through fuse 369 to an amount which does not blow the fim.

The applimflon of voftage to the gate of field effect transistor 375 creates a short circuit path aroundl reentor 373, ailowing a greater cumerd to flow tlunugh fuse 369. Once fuse 869 is blown, the gate of field effect transistor 371 is permanently tied to ground, tlws Iocking field effect transistor 371 in a permanent c=onductirig condition, allowing current to flow from BATTERY I to ground tlvough resist,or 375. This causes linear regulator 359 to go from a OFF conditicn to an ON condition. Linear regulator 359 only operates if there is a voilage difference between the voltage applied to the IN terminal and the OFF terminal. The voltage SUBSTiTUTE SHffT (RULE 26) 'Wo 96124752 . PC.'TIt)896/01612 difference exists only if current can flow from BATTERY 1, through reaistori 357 and field effect transistor 371 to ground. The bbwing of fuse 369 allows current to flow in this path, and ttius turns linear regulator 359 from an ON cond'ition to an OFF condition. Linear regulator 359 raceivea as an input voltage from BATTERY 1, and procluces as an output five voita DC at the OUT terminal. The output of linear regulator 359 supplies power to microprocessor 255 and the other components which cooperate therewith.
Transistor awitch 367 Is provided for selectively enabiing Gnear regulator 359 by application of voltage to the TEST pin. This allows testing of the operaUon of the pressure change detection circuit without requiring the blowing If fuse 369. When five volts DC is applied to the TEST terntinal, transistor switch 367 switches from an OFF conaGtion to an ON cond'ib"on, allowing current to flow from BA7TERY 1, through resisfior 357 and transistor switch 367 to ground, thus enabling operation of linear regulator 359.

16. THE POWER-UP CIRCUIT FOR THE IIIiICROPROCESSOR: Figure 20 is an electrical schematic depiction of a power-up circLdt for microprooessor 255. As is shown in Figure 20, the ONU signal is sv~Ned to the base af switching transWor 269. If ONU goes high, transistor 269 is switched from an OFF condition to an ON condition, alNywing cument to pass from BATTERY 1, through resist,or 397 and =tranaiator 269 to ground. lrnear reguiadtor 399 wili operate only if a voltage difference esisbi between the IN
pin and the OFF pin. Until switching transistor 269 switches from an OFF
condib'on to an ON condition, linear regiAator 399 Is off, and no voltsge is supplied at the OUT pin; however, once switchinB transistor 269 is switched from an OFF conci'ition to an ON candifion, a voitage is developed across resistoa~ 397, and iinear regulator 399 recmives the voitage ot BATTERY I at the IN pin and produces five voits DC as an output which is supplied to both the power pin of microprocessor 256 and the RESET pin of microprocessor 255. Capacitor array 403 are provided as a noise fitter to ensure that the RESET pin is not unintentionaliy triggered. The circuit operates to power-up the microprocessor, when the first biE -raceived from the terminai 91.

SUBS?1TUTE SHEET (RULE 26) WO 96/24752 PCT/[JS96/01612 ~

17. THE COMPUTER PROGRAM: Figures 21A through 220 are flowchart repressnbitions of a computer program which is resident in numory of ROM
257 and EEPROM 259 of Figure 17, and which Is executed by microprocessor 255 to program a partlcular reception apparatus to be responsive to one or two acoustic transmission frequencies.

Figures 21 A and 21 B are a flowchart representation of the preferred user interface routine. The process begins at soRware block 509, wherein microprocessor 255 calls the user interface rou6ne. In accordance with software block 585, mioroprocessor 255 generates and sends an ASCII
character string through magnetic oomrtwnicatjon intsrface circuit 115; if programming t,emiinai 91 Is coupled to reception apparatus 53, the d'ispiay of programming terndnat 91 wiii print a greeting and idenbify the sodlware 9 5 version resident in PROM 257. Next, in accordance with satEware block 587, microprocessor 255 producan an ASCII character string which comprises a user prompt, which lprompta the user to select a parbicuiar operation by depressing a key on programming terminai 91.
Microprocessor 255 then enters a routine for retrieving the subroutine associated with the character selection oF the operator, In accordance with software block 589.

The process continues in saitware block 591, 595, and 599, wherein the user input is analyzed to determine whether the user is reques#ing "test" operations, "initialisetion" operations, or "reading" operations. The program continues at the appropriate software block, including saftware block 593 for testing operationa, soRware block 597 for initiaiization operations, and software block 601 for reading operations. ff the user input is something other than seiection dFthe "T", "!", or "R" keys of programming terminal 91, the computer program continues in software block 603 by printing to programrning ternWna! 91 a message which states that the operator input is "invalid". In order to sirnplify the present discussion, only the initiaiizatjon operabion wi[i be discuesed.

SUBSM'UTE SHEET (RULE 26) ~
The "initialize" functions will nouv be described with reference to Figures 22A through 22D.

If it is detannrined in the fiowctart representstion of the user interface routine of Figures 21A and 21 B that the operator has selected the initiaN7$tion routine, microprocessor 255 performs the operations set forth in the ftawchart representation of Figures 22A th m-eigh 22D. The process begins at software block 845, wheraiin microcrocessor 255 calls the initialitation routine for execution. An optional password protection feature may be provided, which challenges the operator to enter a secret password, in accordance with saftware biook 847, and then examines the entry, in accordance with soRware blocks 849, and 851, to determine whether or not to allow initialization of the wellbore communication apparatus. If the operator passes tlhe. password challenge, the process continues in accordance with acftware block 853, wherein the operator is prompted to identify a particular one of a pluraiity of pre-defined codes which are represented by the arabic numerals I through N, with each arabic numeral representing a pardcular acoustic pulse #ransmission frequency. In accordance with soRware block 855, microprocessor 255 fetches the operator selection, and then prompts the operator to veiify the selection, in accordance with software block 857. In soR.ware block 859, micraprocessor 255 fetches the operators verification of the selected frequency. If, in software block 861, it is determinsd that the operat,or has verFFied the selection, the process ccxrtinues; however, if the operator denies the selection, the operabor is once again pncmptad to select a pre-defined frequency.

In accordance with software block 863, microprocessor 255 prompts the operator to enter a second partiicular acoustic pulse transmission fr+equency. In accordance with saftwara block 865, microprocessw 255 fet,ches the operat,or selection, and then prompts the operat,or to confirm the selection in accordance with aaltware block 867. In accordance with StJBSTiTUTE SHEET(RULE 26) wo 96124752 P[.TII1S96101612 safi.ware block 869, microprocessor 255 fetches the operator's verification or denial of the selected delay interval. If the operator's response is "no", the process raturns to software block 863, wherein the operator is provided another opportunity to enter a delay interval; howewr, if the response is "yes", the process continues at aoftware block 873, wherrein the operator selected frequencies are st,ored in EEPROM 259, and rnicroprocessor r eturns to the main program in accordance with software block 875.

18. COMPL,ETIQN OPERATIONS: The present Invention may find particular utility In conventional weiibore op"ons, such as completion operafiam.
Figures 23A through 23E depict in simpiified fonm one type of completion operetion which can be accomplished with the present invention. Figure 23A depicts wetlbore 2001 whjch is partialiy cased by casing 2003 which is held in poaitfon by oement 2005, but also inciudes uncased portion 2007.
As Is shown In Ftgure 238, an eleaMicaUy-actuable liner hanger medmnism 2011 may be conveyed within wellbare 2001 on tubing string 2009, and set against casing 2003 when a rec:eption apparatus contained within electricaiiy-aatuabie iiner hanger mechanism 2011 recognizes a transrnission frequency which is transmittsd through a wepbowe fluid colurnn. The recmption apparatus portion of liner hanger mechanism 2011 may initiate a power charge reaction which is utilized to set a gripping mechanism into gripping engagement with the interior surface oF casing 2003, as depicted in Figure 23C. 1'ubing string 2009 is then removed from the wellbore. Next, as is depicted in Figure 230, tubing string 2013 may be lowered within weiibore 2001. Tubing string 2013 Includes packer mechanism 2015, valve mechanism 2017, and per[orating gun mechanism 2019. Each of these welJbore devices inciudss a reception apparatus which is preprogrammed to provide an actuation signal upon receptiott of a particular transmission frequency. The acousUc pulses may be sent upon a wellbore fluid column to perforate the weNbore with perforating mechanism 2019, open a sliding sleeve valve with valve mechanisrn 2017, and pack tubular conduit 2013 off against the casing of wellbore 2001. In this configuration, wellbore fluids may flow into welibore 2001 through SUBS71TUT5 SHEfT (RULE 26) WO 96P2.1752 I PGT/US96101612 perforations 2021, and into central bore 2025 of tubular conduit string 201 through openings 2023 of ve'ive "chanism 2017, and be brought to the surface by conventional means, such as; a sucker rod pump mechanism or a submersible pump disposed within the weqbore.
In an altematjve embodiment, a fluid flow regulator valve rnay be inciuded witfiin the tubular conduit atring 2013 which allows the operator to remotely control the amount of fluids flowing from wellbore 2001 to central conduit 2025 of tubuiar conduit strrng 2013.
While the foregoing has described the typea of completion operations which can be performed utiiizing the method and apparat,us for remote control of the present invention, several alternative end devicea will now be discussed In order to provide examples vF actuation techniques which may be utilized in aompletion tools.

Firat, an exploding fastener end device will be discussed. This end device has the outward shape, appearance, and size of an ordinary fastener, such as a bolt; however, the exploding faatener includes an electrically-act,uable power charge disposed within a cavity. The application of current to eleotrical leads will remdt in tiragmentation of the exploding fastener end device.

Second, a Kevlar coupling end device wiq be d'+scussed which utilizzes a Keviar string to tie together portions of a wellbore tool unti'E their separation is desired. An electrical current is applied to a heating elemsnt which is wound about at least a portiion of the Keviar string, to weaken it and cause it to break.

Third, a sliding sleeve assembly end device wili be discussed which includes a piston member which is secured In pcsWtion by a Keviar string or an exploding fastener. When change of the ckleure state of the valve is desired, an eiectrical current Is applied to either the Keviar string or the SUBSTITUTE SHEET (RULE 26) WO 96R4752 PGT/[JS96/01612 exploding fastener, to allow piressure differentials (and preferabiy hydroska8c fluid pressure different{als) to act upon the piston member, to cause it to shift in poeition to change the closure stat,e of the vaive. if the valve is a normally-opened valve, the app[icaEion of electricai current to the electrically,actuabie Keviar string or exploding fast,seer wiU cause the valve to move to a closed conditlon. Conversely, if the valve is norma0iy-closed, app6cation of the electrical current to the Kevlar string or exploding faatener will cause the valve to monre to an open condition.

These particular three end devices will be discussed in detail in the foltowing sections.

19. EXPLODING FASTENER END DE1/iCE; Figure 24 is a longitudinal section view of the preferred explodmg fastener end device of the present invention. Exploding fastener 621 is preferably shaped exteriorJy to conform to the functional requirements of a particular fastener. In the embodiment discussed herein, the paatjc:uiar fastener employed Is a bolt structure. Therefore, exploding fastener 621 includes bolt body 623 which is preferably cyiindricai in shapen but which Includes cavity 625 which contains components which cause the fragmentstion and fracture of bolt body 623 when an eiectrical current is passed inwardly utiiizing electrical leads 647, 649. The exploding fastener 621 may be u6limed with the remoEe control system of the present invention to receive an actuating electricat current through electrical leads 647, 649 when the reception apparatus has determined that the frequency of the aooustic transmissions matches one or more preprogrammedfrequencies.

In the particular embodimEint depicted in Figure 24, bolt body includes external threads 627 at one end, arid seal assembly 829 at the other end. External threads 627 may be machined onto bit body 623 to define any conventional or novel thread type, which thus may be suited for mating with any particular internaUy threaded bor+e. The seal assernbly G29 preferably includes inner lip 631 and outer lip 633 which together define 0-SUBSTlTUTE SHEET (RULE 26) wo 9624752 2187010 PGT1US96101612 ring cavity 635. 0-ring cavity 635 Is adapted to receive annular O-ring seal #
637 therein. In this conf+guration, sead assembly 629 is adapted to farm a sea! with any appropriatefy dimensioned cyiindricai cavity. Preferably, sesi assembly 629 Is disposed in a circular porE. Praferably, thia port leads to a substantially fluid-tight chamber which carries the electricai and efectrai~ic components which make up the recepti4n apparatus or the present inventjon.

Cavity 625 of exploding fastoner 621 includea- power charge 639, which is preferably a heat-actuable lead a2ide,; power charge which expiodes when heated above a predetermined heat threshdd. Heating element 641 extends into power charge 639 and is preferably an electricai resistance heating element which receives electricai current and which generates heat, preferably heat sufficient to exceed the actua6on thr+eshoid of power charge 639. Cavity 625 af exploding fastener 621 additionaQy Includes glass insulating body 643 which elecfrically iaalates heating element 641 to prevent accidental and unintentional discharge of power charge 639 due to stray ourrents or charges. Electrical leads 647, 649 extend through cavity 625 to define the current path to and ffirom heating element 641. Preferably, electrical connectjons are Included in the circuit path defined by electrical lead 647 and electriel lead 649 to allow the disconnection of tbe electrical circuit during intervals of nonuse and transportation. Cavity 625 of exploding fastener 621 further includes sealant 645 which secures the glass insuiating body 643 in position within cavity 625 and which prevents moisture from entering cavity 625 and altering the reactive properties of power charge 639. Additionaity, epoxy body 651 is included within cavity 625 in order to further seal and electrically isolate the power charge 639 and eleatrical conductora of electricai lead 647, 649. As is shown in FJgure 24, end piece 53 Is provided in abutment with seal assembly 629.

Appiication of an electricai current to electrical lead 647 causes an electrical current to pass into exploding fsstener 851, to energize heating 62:

SUBSTRUTE SHEE"T (RULE 26) WO 9Cd24752 } PGT/US9610I522 2'187010 element 641, causing it to generate heat in an amount which is sufficient to trigger the explosion of power charge 639. When power charge 639 explodes, exploding fastener 621 ia fragmented along bolt body 623 between exblernal threads 627 andl seal asaeenbly 629. Explading fastener may be utilized in weAbore toois to secure in position a wellbore tool component which is engaged by enternal threads 827 of exploding fastener 621. For exmnpie, exploding fasfiener 621 may be utilized to secure a aliding or moving component, in order to restrain movement unfil a desired time. The sliding or moving component may be under load, so that fracturing or disintegration of exploding fastener 621 by the passage oF
electrical current into the fastener allows the piece or component to move in the direction of the force bias.

20. THE KEVi,.AR COUPLING END D!C : Figures 25, and 26 depict a Kevlar coupling end device which may be utiiizsd with the remote control apparatus of the present inventiori. Keviar coupling 655 includes Kevlar atring 657 which is utilized to secure one or more otherwise-moveable mechanical cornponents in a wellkore tool. In the particular embodiment depicted in Figure 25, Kevlar strinqa 657 is utiiized to secure C-ring 667 (of which, only the end pieces are shown) in a tight, substantially closed position by applying force to C-ring 657 In the direction of force aerows 669, 671. Preferably, Keviar atring 657 is wrapped about turnbuckles 663, 865, with the ends of Keviar string 657 passed through holes 675, 677. Kevlar string 657 is routed to, and secured in position relative to, anchor component 673, which may connprise a mandrel or other structural component which is fixed in position relative to C-ring 667. Kevlar string 657 is secured in position with to anchor component 673 by soider tabs 679, 681, 683, and 685. Electrical conductors 687, and 689 carry a current which passes through solder tabs 679, and 681, and a conductive, heat generating wire 695 which is conneated therebetween, and which is wrapped around and through Kevlar string 657 in the region intermediate solder tabs 679 and 681. Ukewise, electrical conductors 691 and 693 which carry a current which passes through solder tabs 691 and 693 carry SUBSTiME SliEET (RULE 26) Wo 961t4752 ~ ~ ~ ~ ~ 1 1 0 PC'lY1JS9b/41612 a cument which passes through sdder tabs 683 and 695 which passes through an electrical conductor whiCh, is connected therebetween and which is wrapped around,an4\throiigh Koviar string 657 In the region int,ermediate solder tabs 883 and 686.
The deteils of the electricai and mechanical connection are best described with reference to Figure 26, which is a detail view of sok#er tabs 679, 681, with sokcler tab 681 shown in an intermediafie construction conditlon. As is shown, electrical conductor 887 includes an insulating sheath 699 and an intenially-disposed conductor 701 which is exposed at the end of electrical conductor 687. Electrical conductor 689 is likewise composed of an insuiating sheath 703 disposed over a conductor 705. As is best depicted and described with reference to solder tab 681, the aoider tab is secured to anchor member 673 in a rnanner which defines a pathway between solder tab 681 and anchor component 673 for passage of Kevlar string 857. The electrical cwducba- 705 is located in an inbermad'iate position relative to the remaining portion of soider tab 681. A current carrying heating element 696 is wrapped about eieebical conductor 705 and threaded through and arauid the utrands which make up Koviar string 657. Solder tab 681 is then foided over the electricai conductor 705, and soidered into pasition to ensure a good mechanical and electrical connection at the junction of solder tab 681, electrical conductor 705, and current-carrying heating element 695.

In the preferred embodiment of the present invention, Koviar string 659 comprises a multi-strand Kevlar 29 Aramid braided yarn, such as can be purchased from Western Filaments, ina as Product No. S00KOR 12.
PreferaWy the care diameter of the slring is 0.057 inches, plus or minus 0.005 inches, with a break sfrength vf five hundred pounds, plus or minus ten pounds. Preferably, the material retains ninety percent or more oF ita strength at temperatures up to 480 Fahrenheit, The fiber of Koviar string 657 begins to decompose at 800 Fahrenheit when tested In accordance SUBSTrrUTE SHEET (RULE 26) WO 96f24752 PCTlOS96JO1612 with ASTM D276-80. Preferably, ttie Keviar atrength has a zero strength at temperatrures of 850 Fahrenheit or above.

Also, in the preferred embodiment of the present invention, the current-carrying heating element comprises three inches of nichrome wire, which can be purchased frorn Caiifornin Fine Wire Company of Grover Beach, California, which is aold under the mark of "Stameohm 850", Material No. 100187 annealed 0.005 or 38AWG Wire, 26 Ohms per fook plus or minus three percent ohms per : foot, and add under Part No.
WVXMMN017.

Preferably, in ttm preferred embodiment of the present invention, a battery pack is constructed of nine staves, with each stave being composed of two #lwee-voit Sanyo L.ithium Ceii Batteries (Model No. CR12600SE) .
connected in series to provide six volta. This should provide enough power for the microprocessor and other electrical and electronic components of the reception apparatus, as well as sufficient power to heat (and thus destroy) Kevlar atring 657.

21. TWE SLIDING SLEEVE END DEVICE: Figures 27A through 27D and Figures 28A through 28D are fragmentary iongitudinal section viewa of a sliding sleeve valve insert vahich may be utilized in a completion stxing during compieEion operations to seiectively ailow communication between the central bore of the production tubing stream and the annulus defined between the production tubing sitring and the welibore wall or casing.
Figures 27A through 27D depict one preferred normally-open sliding sieeve valve in accordance with the present invention. Flgures 28A through 28D
depict the same valve in a closed ondition. In accordance with the present invention, the sliding sleeve valve '701 includes threaded connections at its upper and lower ends, which are not depicted in the views vr Figures 27A
through 27D. Sliding sleeve vaive 701 includes a ststionary sleeve asaembiy 703 and a moveable sieeve assembly 705. In the views of Figures 27A and 28A, the stationary sleeve assembly 703 is shown as including SUBSTITUTE SHEET (RULE 26) wa 96124732 PGTlCTS96lo1612 nipple profile 707 which facilitat+es the retrieval of the valve assembly with convsntionai compietton equipment Additionatiy, stationary sieeve assembiy 703 is shown as including sieeve sEop 711 which serves to define the upper iimit of travel for moveable sleeve assembly 705. When moveable sleeve assetnbly 705 is in its normally-opened condition, upper portion 713 is in abutment with sleeve stop 711. In the view of Figure 27A, the upper portion 713 of moveabie sleeve assembAy 705 Is stiawn as Including latch profile 709 which is utilized to engage conventional oompleUon tools to facilitate movement of moveable sleeve assemqfy 705 relative to stationary sleeve assembly 703 after the initial aafiua6on of the sliding sleeve valve 701 (from a normally-opened oondition to a closed condiiion). Latch profile 709 is thus defined as the "up-profile", since it facilitates engagement with a running tool to effect the upward movement of moveable sleeve assembly 705.
Figures 276 and 28B depict some conventionai componends of a seal assembly. The sttucture and various components of the present seal assembly is similar to that depicted, described, and claimed in U.S. Patent No. 5,309,993, entitled "Chevron Seal For A Well Tool", which fssued on May 90,1994 to Coon et al., and which is incorporated herein by reference as if fully set forth. As is shown in Figures 27B and 28B, a seal gland 715 is defined by stationary sleeve assembly 703 and ntoveable sieeve assembly 705 in a position above flowports 725 and 727 in the stationary sleeve assembly 703 and moveable sleeve assembly 705. Likewiee, a seal gland 721 is defined by ststionary sleeve assembly 703 and moveable sleeve assembly 705 in a position below flowfwrta 725, 727. Seai assembly 717 is disposed within seal gland 717, and seal assembly 723 is cfisposed within seal gland 721. Additionally, a cavity Is defined beneath flowport 725 of stationary sleeve assembly 703 which receives a diti;user ring 719. Ail of these components are discussed and described in detail In the Coon et al.
prior art reference. ff the normally-open conditlon, flowports 725, 727 are aligned to allow the passage of fluid between the centrvd bore of the siiding sleeve valve 701 and the annular regiun. As is shown in Fgure 28B, In the SUBSTRUTE SH EFT (RULE 26) closed condition, sliding sleeve valve 701 allows flowport 727 to be positioned beneath seal 723, and thus out of fluid communication with flowport 725. As is shown in both Figures 27B and 28B, moveabfe sleeve assembly 705 includes latch prafibe 729 which is adapted for mating with conventional comple#ing mmiing tools, and which is especially suited for engagement with those rcmning tools in order to move moveable sleeve asaentbly 705 downward relative to stalionary sleeve assernbly 703. In the view of Figure 28B, a conventian,al lal;ch 733 is depicted In phantom as engaging latch prof==ile 729 which alfaws downward movenent of nirnroable sleeve assembly 705. The connection between the latch and ti'se latohing profile breaks with the application of 7,000 pounds of farce. An 0-ring seat assembly 735 is disposed in the lowermost portion of Figure 27B, and includes an enlarged portion which canies upper and lower 0-dng seais 737, 739. The upper and lower 0-dng seais 737, 739 are adapted to provide a moveable sealing engagement between eniarged head 723 and sliding surface 745. An atmospheric charnber 741 is defined downward from 0-dng seal assembly 735. An eiectrical ectLabion of the siid'ing sleeve valve 701 causes the downward rnovement of siiding sleeve valve 731 In response to the pressure dffferential between the atmospheric chamber 741 and the ambient wellbore fluid..

Figure 27C depicts enlargetl head 743 of 0-dng seal assembly 735 in its resting conditjon afber the siidiing sleeve valve 701 is actuatsd for the first time between the normally-closed condition and the opened condition by application of an electrical current to a Kev{ar coupling end device.

Continuing now with Figures 27C and 28C, it will be appreciated that the electronic circuit boards 747 which carry the sensor assembly, logic, microprocessor, and aseociated electrical and electronic components Is located w,ith atmospheric chamber 741 vF s!'iding sleeve valve 701. When one or more acouustic transmissions having the one or more preprogrammed frequencies are detected by the sensors carried within abnospheric chamber 741, an electrical cxurrent is supplied to Kevlar SUBSTITUTE SHEET (RULE 26) WO 46124752 2187010 PCiCliTS96101632 coupling 749 of Figures 27D and 28D. Koviar coupling 749 Is shown in botl*
plan and longitudinal section view in Figures 270 and 28D. As discussed above in considerable detail, Keviar coupling 749 includes a Keviar string 753 which secures the ends 751, 755 oF a C=ring which frts in C-ring groove 757. Kevlar coupling 749 (including the C-ririg) is in abutment with shouider 761 of stationary sleeve assembly 703. O-ring seal assembly 763 is disposed below Koviar coupling 749, and serves to provide a fluid-type siiding interface between moveabie sieeve assembly 705 and stnUonary sleeve assembly 703. When an actuating current is provided to Keviar string 753, It heats and disintegrates, allowing the C-ting to expand. This allows the pressure differential between atmospheric chamber 741 and the ambient pressure to drive moveable sieeve assembly 705 downward reiative to stafionary sleeve assembly 703, with Keviar ooupling 749 corning to rest in the position depicted in Figure 280. Key 765 (best depicted in Figures 28D) is provided adjacent to Keviar coupling 749 in order to aliow for the making and breaking of threaded connections in the drillstring. It serves to keep the assembly locked and resistant to rotation. As moveable sleeve assembly 705 moves downward reiative to stationary sleeve assembly 703, Koviar coupling 749 and key 65 remain in substantially the same location, while the groove 757 which housed Koviar coupling 749 is moved downward with moveable sleeve assembly 705.

In the preferred embodiment of the present invention, once the electrically-actuated sliding siseve valve 701 is moved from a nornnaliy-open condition to a closed condition, the vaive may be moved repeatedly between open and closed conditions throtsgh utilization of a conventional running tool which latches with either the up latch or down latch in order to effect mechanical actuation of a sl'KOng sleeve valve. It will be appreciated by those skilled in the art that the simpii6ed depiczfion of Figures 27A
through 28D omit a housing which surraunds these valve components, and that the insert portion of the valve elone is depicted in Figures 27A through 28D.

SUBSTTTISTE SHEET (RULE 26) While the invention has been shawn in only one of ita fornea, it is not thus lirnited but is suscepti6le to various ahanBea and modifications wlthout departing from the spirit thereof.

SUBSTITUTE SHEEf {RU1.F 26}

Claims

What is claimed is:

1. A method of controlling a remotely located wellbore tool between modes of operation, comprising:
providing (a) an electrically-actuable wellbore tool, (b) an acoustic transmission sensor, and (c) a digital circuit for continually examining, during monitoring operations, detected acoustic transmissions and providing a control signal if a detected acoustic transmission defines a plurality of sequentially transmitted acoustic transmission segments, each defining a particular predetermined actuation frequency;
said digital circuit including:
(i) a detection circuit communicatively coupled to said acoustic transmission sensor for generating a pulse signal corresponding to each one of said acoustic transmissions;
(ii) a counter circuit communicatively coupled to said detection circuit for counting said pulse signal; and (iii) an enabling circuit for selectively enabling said counter circuit wherein said detection circuit, said counter circuit, and said enabling circuit cooperatively operate to cause the generation of said control signal;
securing said electrically-actuable wellbore tool, said acoustic transmission sensor, and said digital circuit to a tubular conduit string;
lowering said tubular conduit string within said wellbore to a selected wellbore location;
providing a wellbore fluid column in contact with a portion of said tubular conduit but out of contact with said acoustic transmission sensor;
generating an acoustic transmission in said wellbore fluid column which defines said plurality of sequentially transmitted acoustic transmission segments; and providing a control signal to said electrically-actuable wellbore tool when said digital circuit determines that said acoustic transmission defines said plurality of sequentially transmitted acoustic transmission segments.

2. A method of controlling a remotely located wellbore tool according to claim 1, further comprising:

during monitoring operations, resetting said digital circuit if it is determined that detected acoustic transmissions define a frequency other than said particular predetermined actuation frequencies.

3. A method of communicating in a wellbore between a transmission node and a reception node, through a fluid column extending therebetween, comprising the method steps of:
providing a transmission apparatus at said transmission node which is in communication with said fluid column;
providing a reception apparatus at said reception node which includes:
(a) a sensor which detects acoustic pulses; and (b) an electronic circuit which examines said acoustic pulses one at a time to determine whether or not they correspond to at least one predefined actuation frequency;
utilizing said transmission apparatus to generate an acoustic transmission in said fluid column; and utilizing said reception apparatus to monitor said acoustic transmission during predefined reception intervals associated with said at least one predefined actuation frequency to (1) provide an actuation signal if said acoustic transmission is determined to correspond to said at least one actuation frequency and (2) reset said electronic circuit if said acoustic transmission is determined to define some frequency other than said at least one predefined actuation frequency.

4. A method of communicating in a wellbore, according to claim 3 wherein said electronic circuit includes:
(a) a pulse counter circuit component; and (b) an enabler member for enabling said pulse counter circuit in a timing pattern corresponding to said at least one predefined actuation frequency which determines said predefined reception intervals.

5. A method of communicating in a wellbore, according to claim 3, wherein during said step of utilizing said reception apparatus, said electronic circuit is automatically reset if an expected pulse is not detected in said predefined reception intervals.

6. A method of switching a remotely located wellbore tool between modes of operation, comprising:
providing (a) an electrically-actuable wellbore tool, (b) an acoustic pulse detection sensor, and (c) a frequency determination circuit;
programming said frequency determination circuit to provide an actuation signal to said electrically-actuable wellbore tool in response to a detection of a particular plurality of sequential acoustic transmission frequencies;
securing said electrically-actuable wellbore tool, said acoustic pulse detection sensor, and said frequency determination circuit to a tubular conduit string;
lowering said tubular conduit string within said wellbore to a selected wellbore location;
providing a wellbore fluid column in contact with a portion of said tubular conduit but out of contact with said acoustic pulse detection sensor;
generating a plurality of acoustic pulse transmissions in said wellbore fluid column;
utilizing said frequency determination circuit to switch said electrically-actuable wellbore tool between modes of operation, when it is determined that said acoustic transmissions match said particular plurality of sequential acoustic transmission frequencies; and resetting said frequency determination circuit if it is determined that said acoustic pulse transmissions correspond to frequencies other than said particular plurality of sequential acoustic transmission.

7. A method of controlling a remotely located wellbore tool between modes of operation, comprising:
providing (a) an electrically-actuable wellbore tool, (b) an acoustic transmission sensor, (c) a digital circuit for continually examining, during monitoring operations, detected acoustic transmissions and providing a control signal if a detected acoustic transmission defines at least one predetermined actuation frequency, and (d) an assignment member for assigning said at least one predetermined actuation frequency to said digital circuit;
said digital circuit including:

(i) a detection circuit communicatively coupled to said acoustic transmission sensor for generating a pulse signal corresponding to each one of said acoustic transmissions;
(ii) a counter circuit communicatively coupled to said detection circuit for counting said pulse signal; and (iii) an enabling circuit for selectively enabling said counter circuit, wherein said detection circuit, said counter circuit, and said enabling circuit cooperatively operate to cause the generation of said control signal;
assigning said at least one predetermined actuation frequency to said digital circuit;
securing said electrically-actuable wellbore tool, said acoustic transmission sensor, and said digital circuit to a tubular conduit string;
lowering said tubular conduit string within said wellbore to a selected wellbore location;
providing a wellbore fluid column in contact with a portion of said tubular conduit;
generating an acoustic transmission in said wellbore fluid column which defines said at least one predetermined actuation frequency; and providing a control signal to said electrically-actuable wellbore tool when said digital circuit determines that said acoustic transmission defines said at least one predetermined actuation frequency.

8. A method of controlling a remotely located wellbore tool, according to claim 7, wherein:
said at least one predetermined actuation frequency is defined by a plurality of consecutively generated acoustic transmission segments, each defining a particular frequency.

9. A method of controlling a remotely located wellbore tool according to claim 8, wherein said step of providing a control signal comprises:
providing a control signal to said electrically-actuable wellbore tool when said digital circuit determines that said plurality of consecutively generated acoustic transmissions define said at least one predetermined actuation frequency.

10. A method of controlling a remotely located wellbore tool according to claim 7, further comprising:
during monitoring operations, resetting said digital circuit if it is determined that said detected acoustic transmission defines a frequency other than said at least one predetermined actuation frequency.

11. A method of controlling a remotely located wellbore tool, according to claim 7, wherein said assignment member assigns at least one discrete predetermined actuation frequency from a set of available discrete predetermined actuation frequencies to said digital circuit.

12. A method of controlling a remotely located wellbore tool according to claim 11, wherein said assignment member includes a programmable controller.

13. A method of controlling a remotely located wellbore tool according to claim 11, wherein:
during said step of assigning, at least an operator-selected one of said set of available discrete predetermined actuation frequencies is assigned to said digital circuit, and is thus identified to said electrically-actuable wellbore tool.

14. An apparatus for communicating a control signal in a wellbore between a transmission node and a reception node, through a fluid column extending therebetween, comprising:
a transmission apparatus at said transmission node which is in communication with said fluid column, for generating an acoustic transmission having at least one acoustic transmission frequency;
a reception apparatus at said reception node which includes: (a) an electrically-actuable wellbore tool, (b) an acoustic transmission sensor, and (c) a digital circuit for continually examining, during monitoring operations, detected acoustic transmissions and providing a control signal if said acoustic transmission defines at least one particular actuation frequency;
wherein, during a communication mode of operation:

(i) said transmission apparatus is utilized to generate said acoustic transmission; and (ii) said reception apparatus is utilized to detect said acoustic transmission in said fluid column; and a reception minimizer for minimizing reception sensitivity of said reception apparatus in a predefined manner by enabling a pulse counting circuit at predetermined times corresponding to said at least one particular actuation frequency.

15. An apparatus for communicating a control signal according to claim 14, wherein said reception minimizer minimizes reception sensitivity of said reception apparatus by disabling at least a portion of said digital circuit for at least one predefined interval during monitoring operations.

16. An apparatus for communicating a control signal, according to claim 15, wherein said at least one predefined interval comprises:
a predefined time interval after detection of a pulse of said acoustic transmission which is detected in a time interval consistent with said at least one particular actuation frequency.

17. An apparatus for communicating a control signal, according to claim 16, wherein said predefined time interval is of a duration sufficient to prevent detection of echo signals associated with each pulse of said acoustic transmission.

18. A method of communicating in a wellbore between a transmission node and a reception node, through a fluid column extending therebetween, comprising the steps of:
providing a transmission apparatus at said transmission node which is in communication with said fluid column including a controller for automatically generating at least one sequence of acoustic pulses which define at least one predefined actuation frequency;
providing a reception apparatus at said reception node which includes:
(a) a sensor means which detects acoustic pulses; and (b) means for examining said acoustic pulses one at a time with a pulse counting circuit to determine whether or not they correspond to said at least one predefined actuation frequency;
utilizing said transmission apparatus to generate an acoustic transmission in said fluid column; and utilizing said reception apparatus to monitor said acoustic transmission to provide an actuation signal if said acoustic transmission is determined to correspond to said at least one predefined actuation frequency.

19. A method of communicating in a wellbore, according to claim 18 wherein said transmission apparatus includes:
(a) a valve assembly for applying a high velocity fluid slug into said fluid column; and (b) a programmable controller for actuating said valve assembly.

20. A method of switching a remotely located wellbore tool between modes of operation, comprising:
providing (a) an electrically-actuable wellbore tool, (b) an acoustic pulse detection sensor, and (c) a frequency determination circuit including a digital counter and a counter enabling circuit;
programming said frequency determination circuit to provide an actuation signal to said electrically-actuable wellbore tool in response to a detection of a particular acoustic transmission frequency;
securing said electrically-actuable wellbore tool, said acoustic pulse detection sensor, and said frequency determination circuit to a tubular conduit string;
lowering said tubular conduit string within said wellbore to a selected wellbore location;
providing a wellbore fluid column in contact with a portion of said tubular conduit;
providing a computer-controlled valve assembly;
generating an acoustic pulse transmission in said wellbore fluid column utilizing said computer-controlled valve assembly; and utilizing said counter enabling circuit to enable said digital counter of said frequency determination circuit to switch said electrically-actuable wellbore tool between modes of operation, when it is determined that said acoustic transmission matches said particular acoustic transmission frequency.